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Medical Essays by Oliver Wendell Holmes, Sr. (The Physician and Poet)

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politicians, with or without a typhoid fever.

Again, see how the "bilious" theory works in every-day life here and
now, illustrated by a case from actual life. A youthful
practitioner, whose last molars have not been a great while cut,
meets an experienced and noted physician in consultation. This is
the case. A slender, lymphatic young woman is suckling two lusty
twins, the intervals of suction being occupied on her part with
palpitations, headaches, giddiness, throbbing in the head, and
various nervous symptoms, her cheeks meantime getting bloodless, and
her strength running away in company with her milk. The old
experienced physician, seeing the yellowish waxy look which is common
in anaemic patients, considers it a "bilious" case, and is for giving
a rousing emetic. Of course, he has to be wheedled out of this, a
recipe is written for beefsteaks and porter, the twins are
ignominiously expelled from the anaemic bosom, and forced to take
prematurely to the bottle, and this prolific mother is saved for
future usefulness in the line of maternity.

The practice of making a profit on the medicine ordered has been held
up to reprobation by one at least of the orators who have preceded
me. That the effect of this has been ruinous in English practice I
cannot doubt, and that in this country the standard of practice was
in former generations lowered through the same agency is not
unlikely. I have seen an old account-book in which the physician
charged an extra price for gilding his rich patients' pills. If all
medicine were very costly, and the expense of it always came out of
the physician's fee, it would really be a less objectionable
arrangement than this other most pernicious one. He would naturally
think twice before he gave an emetic or cathartic which evacuated his
own pocket, and be sparing of the cholagogues that emptied the
biliary ducts of his own wallet, unless he were sure they were
needed. If there is any temptation, it should not be in favor of
giving noxious agents, as it clearly must be in the case of English
druggists and "General Practitioners." The complaint against the
other course is a very old one. Pliny, inspired with as truly Roman
horror of quackery as the elder Cato,--who declared that the Greek
doctors had sworn to exterminate all barbarians, including the
Romans, with their drugs, but is said to have physicked his own wife
to death, notwithstanding,--Pliny says, in so many words, that the
cerates and cataplasms, plasters, collyria, and antidotes, so
abundant in his time, as in more recent days, were mere tricks to
make money.

A pretty strong eddy, then, or rather many eddies, setting constantly
back from the current of sober observation of nature, in the
direction of old superstitions and fancies, of exploded theories, of
old ways of making money, which are very slow to pass out of fashion

But there are other special American influences which we are bound to
take cognizance of. If I wished to show a student the difficulties
of getting at truth from medical experience, I would give him the
history of epilepsy to read. If I wished him to understand the
tendencies of the American medical mind, its sanguine enterprise, its
self-confidence, its audacious handling of Nature, its impatience
with her old-fashioned ways of taking time to get a sick man well, I
would make him read the life and writings of Benjamin Rush. Dr. Rush
thought and said that there were twenty times more intellect and a
hundred times more knowledge in the country in 1799 than before the
Revolution. His own mind was in a perpetual state of exaltation
produced by the stirring scenes in which he had taken a part, and the
quickened life of the time in which he lived. It was not the state
to favor sound, calm observation. He was impatient, and Nature is
profoundly imperturbable. We may adjust the beating of our hearts to
her pendulum if we will and can, but we may be very sure that she
will not change the pendulum's rate of going because our hearts are
palpitating. He thought he had mastered yellow-fever. "Thank God,"
he said, "out of one hundred patients whom I have visited or
prescribed for this day, I have lost none." Where was all his legacy
of knowledge when Norfolk was decimated? Where was it when the blue
flies were buzzing over the coffins of the unburied dead piled up in
the cemetery of New Orleans, at the edge of the huge trenches yawning
to receive them?

One such instance will do as well as twenty. Dr. Rush must have been
a charming teacher, as he was an admirable man. He was observing,
rather than a sound observer; eminently observing, curious, even,
about all manner of things. But he could not help feeling as if
Nature had been a good deal shaken by the Declaration of
Independence, and that American art was getting to be rather too much
for her,--especially as illustrated in his own practice. He taught
thousands of American students, he gave a direction to the medical
mind of the country more than any other one man; perhaps he typifies
it better than any other. It has clearly tended to extravagance in
remedies and trust in remedies, as in everything else. How could a
people which has a revolution once in four years, which has contrived
the Bowie-knife and the revolver, which has chewed the juice out of
all the superlatives in the language in Fourth of July orations, and
so used up its epithets in the rhetoric of abuse that it takes two
great quarto dictionaries to supply the demand; which insists in
sending out yachts and horses and boys to out-sail, out-run, out-
fight, and checkmate all the rest of creation; how could such a
people be content with any but "heroic" practice? What wonder that
the stars and stripes wave over doses of ninety grains of sulphate of
quinine, [More strictly, ninety-six grains in two hours. Dunglison's
Practice, 1842, vol. ii. p. 520. Eighty grains in one dose.
Ibid. p. 536. Ninety-six grains of sulphate of quinine are equal
to eight ounces of good bark.--Wood & Bache.] and that the American
eagle screams with delight to see three drachms of calomel given at a
single mouthful?

Add to this the great number of Medical Journals, all useful, we
hope, most of them necessary, we trust, many of them excellently well
conducted, but which must find something to fill their columns, and
so print all the new plans of treatment and new remedies they can get
hold of, as the newspapers, from a similar necessity, print the
shocking catastrophes and terrible murders.

Besides all this, here are we, the great body of teachers in the
numberless medical schools of the Union, some of us lecturing to
crowds who clap and stamp in the cities, some of us wandering over
the country, like other professional fertilizers, to fecundate the
minds of less demonstrative audiences at various scientific stations;
all of us talking habitually to those supposed to know less than
ourselves, and loving to claim as much for our art as we can, not to
say for our own schools, and possibly indirectly for our own
practical skill. Hence that annual crop of introductory lectures;
the useful blossoming into the ornamental, as the cabbage becomes
glorified in the cauliflower; that lecture-room literature of
adjectives, that declamatory exaggeration, that splendid show of
erudition borrowed from D'Israeli, and credited to Lord Bacon and the
rest, which have suggested to our friends of the Medical Journals an
occasional epigram at our expense. Hence the tendency in these
productions, and in medical lectures generally, to overstate the
efficacy of favorite methods of cure, and hence the premium offered
for showy talkers rather than sagacious observers, for the men of
adjectives rather than of nouns substantive in the more ambitious of
these institutions.

Such are some of the eddies in which we are liable to become involved
and carried back out of the broad stream of philosophical, or, in
other words, truth-loving, investigations. The causes of disease, in
the mean time, have been less earnestly studied in the eagerness of
the search for remedies. Speak softly! Women have been borne out
from an old-world hospital, two in one coffin, that the horrors of
their prison-house might not be known, while the very men who were
discussing the treatment of the disease were stupidly conveying the
infection from bed to bed, as rat-killers carry their poisons from
one household to another. Do not some of you remember that I have
had to fight this private-pestilence question against a scepticism
which sneered in the face of a mass of evidence such as the calm
statisticians of the Insurance office could not listen to without
horror and indignation? ["The Contagiousness of Puerperal Fever."--
N. E. Quar. Jour. of Medicine and Surgery, April, 1843. Reprinted,
with Additions. Boston: Ticknor & Fields. 1855.] Have we forgotten
what is told in one of the books published under our own sanction,
that a simple measure of ventilation, proposed by Dr. John Clark, had
saved more than sixteen thousand children's lives in a single
hospital? How long would it have taken small doses of calomel and
rhubarb to save as many children? These may be useful in prudent
hands, but how insignificant compared to the great hygienic
conditions! Causes, causes, and again causes,--more and more we fall
back on these as the chief objects of our attention. The shortest
system of medical practice that I know of is the oldest, but not the
worst. It is older than Hippocrates, older than Chiron the Centaur.
Nature taught it to the first mother when she saw her first-born
child putting some ugly pebble or lurid berry into its mouth. I know
not in what language it was spoken, but I know that in English it
would sound thus: Spit it out!

Art can do something more than say this. It can sometimes reach the
pebble or berry after it has been swallowed. But the great thing is
to keep these things out of children's mouths, and as soon as they
are beyond our reach, to be reasonable and patient with Nature, who
means well, but does not like to hurry, and who took nine calendar
months, more or less, to every mother's son among us, before she
thought he was fit to be shown to the public.

Suffer me now to lay down a few propositions, whether old or new it
matters little, not for your immediate acceptance, nor yet for your
hasty rejection, but for your calm consideration.

But first, there are a number of terms which we are in the habit of
using in a vague though not unintelligible way, and which it is as
well now to define. These terms are the tools with which we are to
work, and the first thing is to sharpen them. It is nothing to us
that they have been sharpened a thousand times before; they always
get dull in the using, and every new workman has a right to carry
them to the grindstone and sharpen them to suit himself.

Nature, in medical language, as opposed to Art, means trust in the
reactions of the living system against, ordinary normal impressions.

Art, in the same language, as opposed to Nature, means an intentional
resort to extraordinary abnormal impressions for the relief of

The reaction of the living system is the essence of both. Food is
nothing, if there is no digestive act to respond to it. We cannot
raise a blister on a dead man, or hope that a carminative forced
between his lips will produce its ordinary happy effect.

Disease, dis-ease,--disturbed quiet, uncomfortableness,--means
imperfect or abnormal reaction of the living system, and its more or
less permanent results.

Food, in its largest sense, is whatever helps to build up the normal
structures, or to maintain their natural actions.

Medicine, in distinction from food, is every unnatural or noxious
agent applied for the relief of disease.

Physic means properly the Natural art, and Physician is only the
Greek synonyme of Naturalist.

With these few explanations I proceed to unfold the propositions I
have mentioned.

Disease and death, if we may judge by the records of creation, are
inherently and essentially necessary in the present order of things.
A perfect intelligence, trained by a perfect education, could do no
more than keep the laws of the physical and spiritual universe. An
imperfect intelligence, imperfectly taught,--and this is the
condition of our finite humanity,--will certainly fail to keep all
these laws perfectly. Disease is one of the penalties of one of the
forms of such failure. It is prefigured in the perturbations of the
planets, in the disintegration of the elemental masses; it has left
its traces in the fossil organisms of extinct creations. [Professor
Agassiz has kindly handed me the following note: "There are abnormal
structures in animals of all ages anterior to the creation of
mankind. Malformed specimens of Crinoids are known from the Triassic
and Jurassic deposits. Malformed and diseased bones of tertiary
mammalia have been collected in the caverns of Gailenreuth with
traces of healing."]

But it is especially the prerogative, I had almost said privilege, of
educated and domesticated beings, from man down to the potato,
serving to teach them, and such as train them, the laws of life, and
to get rid of those who will not mind or cannot be kept subject to
these laws.

Disease, being always an effect, is always in exact proportion to the
sum of its causes, as much in the case of Spigelius, who dies of a
scratch, as in that of the man who recovers after an iron bar has
been shot through his brain. The one prevalent failing of the
medical art is to neglect the causes and quarrel with the effect.

There are certain general facts which include a good deal of what is
called and treated as disease. Thus, there are two opposite
movements of life to be seen in cities and elsewhere, belonging to
races which, from various persistent causes, are breeding down and
tending to run out, and to races which are breeding up, or
accumulating vital capital,--a descending and an ascending series.
Let me give an example of each; and that I may incidentally remove a
common impression about this country as compared with the Old World,
an impression which got tipsy with conceit and staggered into the
attitude of a formal proposition in the work of Dr. Robert Knox, I
will illustrate the downward movement from English experience, and
the upward movement from a family history belonging to this immediate

Miss Nightingale speaks of "the fact so often seen of a
great-grandmother, who was a tower of physical vigor, descending into
a grandmother perhaps a little less vigorous, but still sound as a
bell, and healthy to the core, into a mother languid and confined to
her carriage and house; and lastly into a daughter sickly and
confined to her bed." So much for the descending English series; now
for the ascending American series.

Something more than one hundred and thirty years ago there graduated
at Harvard College a delicate youth, who lived an invalid life and
died at the age of about fifty. His two children were both of
moderate physical power, and one of them diminutive in stature. The
next generation rose in physical development, and reached eighty
years of age and more in some of its members. The fourth generation
was of fair average endowment. The fifth generation, great-great-
grandchildren of the slender invalid, are several of, them of
extraordinary bodily and mental power; large in stature, formidable
alike with their brains and their arms, organized on a more extensive
scale than either of their parents.

This brief account illustrates incidentally the fallacy of the
universal-degeneration theory applied to American life; the same on
which one of our countrymen has lately brought some very forcible
facts to bear in a muscular discussion of which we have heard rather
more than is good for us. But the two series, American and English,
ascending and descending, were adduced with the main purpose of
showing the immense difference of vital endowments in different
strains of blood; a difference to which all ordinary medication is in
all probability a matter of comparatively trivial purport. Many
affections which art has to strive against might be easily shown to
be vital to the well-being of society. Hydrocephalus, tabes
mesenterica, and other similar maladies, are natural agencies which
cut off the children of races that are sinking below the decent
minimum which nature has established as the condition of viability,
before they reach the age of reproduction. They are really not so
much diseases, as manifestations of congenital incapacity for life;
the race would be ruined if art could ever learn always to preserve
the individuals subject to them. We must do the best we can for
them, but we ought also to know what these "diseases" mean.

Again, invalidism is the normal state of many organizations. It can
be changed to disease, but never to absolute health by medicinal
appliances. There are many ladies, ancient and recent, who are
perpetually taking remedies for irremediable pains and aches. They
ought to have headaches and back-aches and stomach-aches; they are
not well if they do not have them. To expect them to live without
frequent twinges is like expecting a doctor's old chaise to go
without creaking; if it did, we might be sure the springs were
broken. There is no doubt that the constant demand for medicinal
remedies from patients of this class leads to their over-use; often
in the case of cathartics, sometimes in that of opiates. I have been
told by an intelligent practitioner in a Western town, that the
constant prescription of opiates by certain physicians in his
vicinity has rendered the habitual use of that drug in all that
region very prevalent; more common, I should think, than alcoholic
drunkenness in the most intemperate localities of which I have known
anything. A frightful endemic demoralization betrays itself in the
frequency with which the haggard features and drooping shoulders of
the opium-drunkards are met with in the streets.

The next proposition I would ask you to consider is this:
The presumption always is that every noxious agent, including
medicines proper, which hurts a well man, hurts a sick one.
[ Note B.]

Let me illustrate this proposition before you decide upon it. If it
were known that a prize-fighter were to have a drastic purgative
administered two or three days before a contest, or a large blister
applied to his back, no one will question that it would affect the
betting on his side unfavorably; we will say to the amount of five
per cent. Now the drain upon the resources of the system produced in
such a case must be at its minimum, for the subject is a powerful
man, in the prime of life, and in admirable condition. If the drug
or the blister takes five per cent. from his force of resistance, it
will take at least as large a fraction from any invalid. But this
invalid has to fight a champion who strikes hard but cannot be hit in
return, who will press him sharply for breath, but will never pant
himself while the wind can whistle through his fleshless ribs. The
suffering combatant is liable to want all his stamina, and five per
cent. may lose him the battle.

All noxious agents, all appliances which are not natural food or
stimuli, all medicines proper, cost a patient, on the average, five
per cent. of his vital force, let us say. Twenty times as much waste
of force produced by any of them, that is, would exactly kill him,
nothing less than kill him, and nothing more. If this, or something
like this, is true, then all these medications are, prima facie,

In the game of Life-or-Death, Rouge et Noir, as played between the
Doctor and the Sexton, this five per cent., this certain small injury
entering into the chances is clearly the sexton's perquisite for
keeping the green table, over which the game is played, and where he
hoards up his gains. Suppose a blister to diminish a man's pain,
effusion or dyspnoea to the saving of twenty per cent. in vital
force; his profit from it is fifteen, in that case, for it always
hurts him five to begin with, according to our previous assumption.

Presumptions are of vast importance in medicine, as in law. A man is
presumed innocent until he is proved guilty. A medicine--that is, a
noxious agent, like a blister, a seton, an emetic, or a cathartic--
should always be presumed to be hurtful. It always is directly
hurtful; it may sometimes be indirectly beneficial. If this
presumption were established, and disease always assumed to be the
innocent victim of circumstances, and not punishable by medicines,
that is, noxious agents, or poisons, until the contrary was shown, we
should not so frequently hear the remark commonly, perhaps
erroneously, attributed to Sir Astley Cooper, but often repeated by
sensible persons, that, on the whole, more harm than good is done by
medication. Throw out opium, which the Creator himself seems to
prescribe, for we often see the scarlet poppy growing in the
cornfields, as if it were foreseen that wherever there is hunger to
be fed there must also be pain to be soothed; throw out a few
specifics which our art did not discover, and is hardly needed to
apply [ Note C.]; throw out wine, which is a food, and the vapors
which produce the miracle of anaesthesia, and I firmly believe that
if the whole materia medica, as now used, could be sunk to the bottom
of the sea, it would be all the better for mankind,--and all the
worse for the fishes.

But to justify this proposition, I must add that the injuries
inflicted by over-medication are to a great extent masked by disease.
Dr. Hooker believes that the typhus syncopatia of a preceding
generation in New England "was often in fact a brandy and opium
disease." How is a physician to distinguish the irritation produced
by his blister from that caused by the inflammation it was meant to
cure? How can he tell the exhaustion produced by his evacuants from
the collapse belonging to the disease they were meant to remove?

Lastly, medication without insuring favorable hygienic conditions is
like amputation without ligatures. I had a chance to learn this well
of old, when physician to the Broad Street district of the Boston
Dispensary. There, there was no help for the utter want of wholesome
conditions, and if anybody got well under my care, it must have been
in virtue of the rough-and-tumble constitution which emerges from the
struggle for life in the street gutters, rather than by the aid of my

But if the materia medica were lost overboard, how much more pains
would be taken in ordering all the circumstances surrounding the
patient (as can be done everywhere out of the crowded pauper
districts), than are taken now by too many who think they do their
duty and earn their money when they write a recipe for a patient left
in an atmosphere of domestic malaria, or to the most negligent kind
of nursing! I confess that I should think my chance of recovery from
illness less with Hippocrates for my physician and Mrs. Gamp for my
nurse, than if I were in the hands of Hahnemann himself, with
Florence Nightingale or good Rebecca Taylor to care for me.

If I am right in maintaining that the presumption is always against
the use of noxious agents in disease, and if any whom I might
influence should adopt this as a principle of practice, they will
often find themselves embarrassed by the imperative demand of
patients and their friends for such agents where a case is not made
out against this standing presumption. I must be permitted to say,
that I think the French, a not wholly uncivilized people, are in
advance of the English and ourselves in the art of prescribing for
the sick without hurting them. And I do confess that I think their
varied ptisans and syrups are as much preferable to the mineral
regimen of bug-poison and ratsbane, so long in favor on the other
side of the Channel, as their art of preparing food for the table to
the rude cookery of those hard-feeding and much-dosing islanders.
We want a reorganized cuisine of invalidism perhaps as much as the
culinary, reform, for which our lyceum lecturers, and others who live
much at hotels and taverns, are so urgent. Will you think I am
disrespectful if I ask whether, even in Massachusetts, a dose of
calomel is not sometimes given by a physician on the same principle
as that upon which a landlord occasionally prescribes bacon and
eggs,--because he cannot think of anything else quite so handy? I
leave my suggestion of borrowing a hint from French practice to your
mature consideration.

I may, however, call your attention, briefly, to the singular fact,
that English and American practitioners are apt to accuse French
medical practice of inertness, and French surgical practice of
unnecessary activity. Thus, Dr. Bostock considers French medical
treatment, with certain exceptions, as "decidedly less effective"
than that of his own country. Mr. S. Cooper, again, defends the
simple British practice of procuring union by the first intention
against the attacks of M. Roux and Baron Larrey. [Cooper's Surg.
Diet. art. "Wounds." Yet Mr. John Bell gives the French surgeons
credit for introducing this doctrine of adhesion, and accuses
O'Halloran of "rudeness and ignorance," and "bold, uncivil language,"
in disputing their teaching. Princ. of Surgery, vol. i. p. 42.
Mr. Hunter succeeded at last in naturalizing the doctrine and
practice, but even he had to struggle against the perpetual jealousy
of rivals, and died at length assassinated by an insult.] We have
often heard similar opinions maintained by our own countrymen. While
Anglo-American criticism blows hot or cold on the two departments of
French practice, it is not, I hope, indecent to question whether all
the wisdom is necessarily with us in both cases.

Our art has had two or three lessons which have a deep meaning to
those who are willing to read them honestly. The use of water-
dressings in surgery completed the series of reforms by which was
abolished the "coarse and cruel practice" of the older surgeons, who
with their dressings and acrid balsams, their tents and leaden tubes,
"absolutely delayed the cure." The doctrine of Broussais, transient
as was its empire, reversed the practice of half of Christendom for a
season, and taught its hasty disciples to shun their old favorite
remedies as mortal poisons. This was not enough permanently to shift
the presumption about drugs where it belonged, and so at last, just
as the sympathetic powder and the Unguentum Armarium came in a
superstitious age to kill out the abuses of external over-medication,
the solemn farce of Homoeopathy was enacted in the face of our own
too credulous civilization, that under shelter of its pretences the
"inward bruises" of over-drugged viscera might be allowed to heal by
the first intention. Its lesson we must accept, whether we will or
not; its follies we are tired of talking about. The security of the
medical profession against this and all similar fancies is in the
average constitution of the human. mind with regard to the laws of

My friends and brothers in Art! There is nothing to be feared from
the utterance of any seeming heresy to which you may have listened.
I cannot compromise your collective wisdom. If I have strained the
truth one hair's breadth for the sake of an epigram or an antithesis,
you are accustomed to count the normal pulse-beats of sound judgment,
and know full well how to recognize the fever-throbs of conceit and
the nervous palpitations of rhetoric.

The freedom with which each of us speaks his thought in this
presence, belongs in part to the assured position of the Profession
in our Commonwealth, to the attitude of Science, which is always
fearless, and to the genius of the soil on which we stand, from which
Nature withheld the fatal gift of malaria only to fill it with
exhalations that breed the fever of inquiry in our blood and in our
brain. But mainly we owe the large license of speech we enjoy to
those influences and privileges common to us all as self-governing

This Republic is the chosen home of minorities, of the less power in
the presence of the greater. It is a common error to speak of our
distinction as consisting in the rule of the majority. Majorities,
the greater material powers, have always ruled before. The history
of most countries has been that of majorities, mounted majorities,
clad in iron, armed with death treading down the tenfold more
numerous minorities. In the old civilizations they root themselves
like oaks in the soil; men must live in their shadow or cut them
down. With us the majority is only the flower of the passing noon,
and the minority is the bud which may open in the next morning's sun.
We must be tolerant, for the thought which stammers on a single
tongue today may organize itself in the growing consciousness of the
time, and come back to us like the voice of the multitudinous waves
of the ocean on the morrow.

Twenty-five years have passed since one of your honored Presidents
spoke to this Society of certain limitations to the power of our Art,
now very generally conceded. Some were troubled, some were almost
angry, thinking the Profession might suffer from such concessions.
It has certainly not suffered here; if, as some affirm, it has lost
respect anywhere, it was probably for other, and no doubt sufficient

Since that time the civilization of this planet has changed hands.
Strike out of existence at this moment every person who was breathing
on that day, May 27, 1835, and every institution of society, every
art and every science would remain intact and complete in the living
that would be left. Every idea the world then held has been since
dissolved and recrystallized.

We are repeating the same process. Not to make silver shrines for
our old divinities, even though by this craft we should have our
wealth, was this Society organized and carried on by the good men and
true who went before us. Not for this, but to melt the gold out of
the past, though its dross should fly in dust to all the winds of
heaven, to save all our old treasures of knowledge and mine deeply
for new, to cultivate that mutual respect of which outward courtesy
is the sign, to work together, to feel together, to take counsel
together, and to stand together for the truth, now, always, here,
everywhere; for this our fathers instituted, and we accept, the
offices and duties of this time-honored Society.


An Introductory Lecture delivered before the Medical Class
of Harvard University, November 6, 1861.

[This Lecture appears as it would have been delivered had the time
allowed been less strictly, limited. Passages necessarily omitted
have been restored, and points briefly touched have been more fully
considered. A few notes have been added for the benefit of that
limited class of students who care to track an author through the
highways and by-ways of his reading. I owe my thanks to several of
my professional brethren who have communicated with me on subjects
with which they are familiar; especially to Dr. John Dean, for the
opportunity of profiting by his unpublished labors, and to Dr. Hasket
Derby, for information and references to recent authorities relating
to the anatomy and physiology of the eye.]

The entrance upon a new course of Lectures is always a period of
interest to instructors and pupils. As the birth of a child to a
parent, so is the advent of a new class to a teacher. As the light
of the untried world to the infant, so is the dawning of the light
resting over the unexplored realms of science to the student. In the
name of the Faculty I welcome you, Gentlemen of the Medical Class,
new-born babes of science, or lustier nurslings, to this morning of
your medical life, and to the arms and the bosom of this ancient
University. Fourteen years ago I stood in this place for the first
time to address those who occupied these benches. As I recall these
past seasons of our joint labors, I feel that they have been on the
whole prosperous, and not undeserving of their prosperity.

For it has been my privilege to be associated with a body of true and
faithful workers; I cannot praise them freely to their faces, or I
should be proud to discourse of the harmonious diligence and the
noble spirit in which they have toiled together, not merely to teach
their several branches, but to elevate the whole standard of

I may speak with less restraint of those gentlemen who have aided me
in the most laborious part of my daily duties, the Demonstrators, to
whom the successive classes have owed so much of their instruction.
They rise before me, the dead and the living, in the midst of the
most grateful recollections. The fair, manly face and stately figure
of my friend, Dr. Samuel Parkman, himself fit for the highest offices
of teaching, yet willing to be my faithful assistant in the time of
need, come back to me with the long sigh of regret for his early loss
to our earthly companionship. Every year I speak the eulogy of Dr.
Ainsworth's patient toil as I show his elaborate preparations: When I
take down my "American Cyclopaedia" and borrow instruction from the
learned articles of Dr. Kneeland, I cease to regret that his
indefatigable and intelligent industry was turned into a broader
channel. And what can I say too cordial of my long associated
companion and friend, Dr. Hodges, whose admirable skill, working
through the swiftest and surest fingers that ever held a scalpel
among us, has delighted class after class, and filled our Museum with
monuments which will convey his name to unborn generations?

This day belongs, however, not to myself and my recollections, but to
all of us who teach and all of you who listen, whether experts in our
specialties or aliens to their mysteries, or timid neophytes just
entering the portals of the hall of science. Look in with me, then,
while I attempt to throw some rays into its interior, which shall
illuminate a few of its pillars and cornices, and show at the same
time how many niches and alcoves remain in darkness.

SCIENCE is the topography of ignorance. From a few elevated points
we triangulate vast spaces, inclosing infinite unknown details. We
cast the lead, and draw up a little sand from abysses we may never
reach with our dredges.

The best part of our knowledge is that which teaches us where
knowledge leaves off and ignorance begins. Nothing more clearly
separates a vulgar from a superior mind, than the confusion in the
first between the little that it truly knows, on the one hand, and
what it half knows and what it thinks it knows on the other.

That which is true of every subject is especially true of the branch
of knowledge which deals with living beings. Their existence is a
perpetual death and reanimation. Their identity is only an idea, for
we put off our bodies many times during our lives, and dress in new
suits of bones and muscles.

"Thou art not thyself;
For thou exist'st on many a thousand grains
That issue out of dust."

If it is true that we understand ourselves but imperfectly in health,
this truth is more signally manifested in disease, where natural
actions imperfectly understood, disturbed in an obscure way by half-
seen causes, are creeping and winding along in the dark toward their
destined issue, sometimes using our remedies as safe stepping-stones,
occasionally, it may be, stumbling over them as obstacles.

I propose in this lecture to show you some points of contact between
our ignorance and our knowledge in several of the branches upon the
study of which you are entering. I may teach you a very little
directly, but I hope much more from the trains of thought I shall
suggest. Do not expect too much ground to be covered in this rapid
survey. Our task is only that of sending out a few pickets under the
starry flag of science to the edge of that dark domain where the
ensigns of the obstinate rebel, Ignorance, are flying undisputed. We
are not making a reconnoissance in force, still less advancing with
the main column. But here are a few roads along which we have to
march together, and we wish to see clearly how far our lines extend,
and where the enemy's outposts begin.

Before touching the branches of knowledge that deal with organization
and vital functions, let us glance at that science which meets you at
the threshold of your study, and prepares you in some measure to deal
with the more complex problems of the living laboratory.

CHEMISTRY. includes the art of separating and combining the elements
of matter, and the study of the changes produced by these operations.
We can hardly say too much of what it has contributed to our
knowledge of the universe and our power of dealing with its
materials. It has given us a catalogue raisonne of the substances
found upon our planet, and shown how everything living and dead is
put together from them. It is accomplishing wonders before us every
day, such as Arabian story-tellers used to string together in their
fables. It spreads the, sensitive film on the artificial retina
which looks upon us through the optician's lens for a few seconds,
and fixes an image that will outlive its original. It questions the
light of the sun, and detects the vaporized metals floating around
the great luminary,--iron, sodium, lithium, and the rest,--as if the
chemist of our remote planet could fill his bell-glasses from its
fiery atmosphere. It lends the power which flashes our messages in
thrills that leave the lazy chariot of day behind them. It seals up
a few dark grains in iron vases, and lo! at the touch of a single
spark, rises in smoke and flame a mighty Afrit with a voice like
thunder and an arm that shatters like an earthquake. The dreams of
Oriental fancy have become the sober facts of our every-day life, and
the chemist is the magician to whom we owe them.

To return to the colder scientific aspect of chemistry. It has shown
us how bodies stand affected to each other through an almost
boundless range of combinations. It has given us a most ingenious
theory to account for certain fixed relations in these combinations.
It has successfully eliminated a great number of proximate compounds,
more or less stable, from organic structures. It has invented others
which form the basis of long series of well-known composite
substances. In fact, we are perhaps becoming overburdened with our
list of proximate principles, demonstrated and hypothetical.

How much nearer have we come to the secret of force than Lully and
Geber and the whole crew of juggling alchemists? We have learned a
great deal about the how, what have we learned about the why?

Why does iron rust, while gold remains untarnished, and gold
amalgamate, while iron refuses the alliance of mercury?

The alchemists called gold Sol, the sun, and iron Mars, and pleased
themselves with fancied relations between these substances and the
heavenly bodies, by which they pretended to explain the facts they
observed. Some of their superstitions have lingered in practical
medicine to the present day, but chemistry has grown wise enough to
confess the fact of absolute ignorance.

What is it that makes common salt crystallize in the form of cubes,
and saltpetre in the shape of six-sided prisms? We see no reason why
it should not have been just the other way, salt in prisms and
saltpetre in cubes, or why either should take an exact geometrical
outline, any more than coagulating albumen.

But although we had given up attempting to explain the essential
nature of affinities and of crystalline types, we might have supposed
that we had at least fixed the identity of the substances with which
we deal, and determined the laws of their combination. All at once
we find that a simple substance changes face, puts off its
characteristic qualities and resumes them at will;--not merely when
we liquefy or vaporize a solid, or reverse the process; but that a
solid is literally transformed into another solid under our own eyes.
We thought we knew phosphorus. We warm a portion of it sealed in an
empty tube, for about a week. It has become a brown infusible
substance, which does not shine in the dark nor oxidate in the air.
We heat it to 500 F., and it becomes common phosphorus again. We
transmute sulphur in the same singular way. Nature, you know, gives
us carbon in the shape of coal and in that of the diamond. It is
easy to call these changes by the name allotropism, but not the less
do they confound our hasty generalizations.

These facts of allotropism have some corollaries connected with them
rather startling to us of the nineteenth century. There may be other
transmutations possible besides those of phosphorus and sulphur.
When Dr. Prout, in 1840, talked about azote and carbon being "formed"
in the living system, it was looked upon as one of those freaks of
fancy to which philosophers, like other men, are subject. But when
Professor Faraday, in 1851, says, at a meeting of the British
Association, that "his hopes are in the direction of proving that
bodies called simple were really compounds, and may be formed
artificially as soon as we are masters of the laws influencing their
combinations,"--when he comes forward and says that he has tried
experiments at transmutation, and means, if his life is spared, to
try them again,--how can we be surprised at the popular story of
1861, that Louis Napoleon has established a gold-factory and is
glutting the mints of Europe with bullion of his own making?

And so with reference to the law of combinations. The old maxim was,
Corpora non agunt nisi soluta. If two substances, a and b, are
inclosed in a glass vessel, c, we do not expect the glass to change
them, unless a or b or the compound a b has the power of dissolving
the glass. But if for a I take oxygen, for b hydrogen, and for c a
piece of spongy platinum, I find the first two combine with the
common signs of combustion and form water, the third in the mean time
undergoing no perceptible change. It has played the part of the
unwedded priest, who marries a pair without taking a fee or having
any further relation with the parties. We call this catalysis,
catalytic action, the action of presence, or by what learned name we
choose. Give what name to it we will, it is a manifestation of power
which crosses our established laws of combination at a very open
angle of intersection. I think we may find an analogy for it in
electrical induction, the disturbance of the equilibrium of the
electricity of a body by the approach of a charged body to it,
without interchange of electrical conditions between the two bodies.
But an analogy is not an explanation, and why a few drops of yeast
should change a saccharine mixture to carbonic acid and alcohol,--a
little leaven leavening the whole lump,--not by combining with it,
but by setting a movement at work, we not only cannot explain, but
the fact is such an exception to the recognized laws of combination
that Liebig is unwilling to admit the new force at all to which
Berzelius had given the name so generally accepted.

The phenomena of isomerism, or identity of composition and
proportions of constituents with difference of qualities, and of
isomorphism, or identity of form in crystals which have one element
substituted for another, were equally surprises to science; and
although the mechanism by which they are brought about can be to a
certain extent explained by a reference to the hypothetical atoms of
which the elements are constituted, yet this is only turning the
difficulty into a fraction with an infinitesimal denominator and an
infinite numerator.

So far we have studied the working of force and its seeming anomalies
in purely chemical phenomena. But we soon find that chemical force
is developed by various other physical agencies,--by heat, by light,
by electricity, by magnetism, by mechanical agencies; and, vice
versa, that chemical action develops heat, light, electricity,
magnetism, mechanical force, as we see in our matches, galvanic
batteries, and explosive compounds. Proceeding with our experiments,
we find that every kind of force is capable of producing all other
kinds, or, in Mr. Faraday's language, that "the various forms under
which the forces of matter are made manifest have a common origin,
or, in other words, are so directly related and mutually dependent
that they are convertible one into another."

Out of this doctrine naturally springs that of the conservation of
force, so ably illustrated by Mr. Grove, Dr. Carpenter, and Mr.
Faraday. This idea is no novelty, though it seems so at first sight.
It was maintained and disputed among the giants of philosophy.
Des Cartes and Leibnitz denied that any new motion originated in
nature, or that any ever ceased to exist; all motion being in a
circle, passing from one body to another, one losing what the other
gained. Newton, on the other hand, believed that new motions were
generated and existing ones destroyed. On the first supposition,
there is a fixed amount of force always circulating in the universe.
On the second, the total amount may be increasing or diminishing.
You will find in the "Annual of Scientific Discovery" for 1858 a very
interesting lecture by Professor Helmholtz of Bonn, in which it is
maintained that a certain portion of force is lost in every natural
process, being converted into unchangeable heat, so that the universe
will come to a stand-still at last, all force passing into heat, and
all heat into a state of equilibrium.

The doctrines of the convertibility or specific equivalence of the
various forms of force, and of its conservation, which is its logical
consequence, are very generally accepted, as I believe, at the
present time, among physicists. We are naturally led to the
question, What is the nature of force? The three illustrious
philosophers just referred to agree in attributing the general
movements of the universe to the immediate Divine action. The
doctrine of "preestablished harmony" was an especial contrivance of
Leibnitz to remove the Creator from unworthy association with the
less divine acts of living beings. Obsolete as this expression
sounds to our ears, the phrase laws of the universe, which we use so
constantly with a wider application, appears to me essentially
identical with it.

Force does not admit of explanation, nor of proper definition, any
more than the hypothetical substratum of matter. If we assume the
Infinite as omnipresent, omniscient, omnipotent, we cannot suppose
Him excluded from any part of His creation, except from rebellious
souls which voluntarily exclude Him by the exercise of their fatal
prerogative of free-will. Force, then, is the act of immanent
Divinity. I find no meaning in mechanical explanations. Newton's
hypothesis of an ether filling the heavenly spaces does not, I
confess, help my conceptions. I will, and the muscles of my vocal
organs shape my speech. God wills, and the universe articulates His
power, wisdom, and goodness. That is all I know. There is no bridge
my mind can throw from the "immaterial" cause to the "material"

The problem of force meets us everywhere, and I prefer to encounter
it in the world of physical phenomena before reaching that of living
actions. It is only the name for the incomprehensible cause of
certain changes known to our consciousness, and assumed to be outside
of it. For me it is the Deity Himself in action.

I can therefore see a large significance in the somewhat bold
language of Burdach: "There is for me but one miracle, that of
infinite existence, and but one mystery, the manner in which the
finite proceeds from the infinite. So soon as we recognize this
incomprehensible act as the general and primordial miracle, of which
our reason perceives the necessity, but the manner of which our
intelligence cannot grasp, so soon as we contemplate the nature known
to us by experience in this light, there is for us no other
impenetrable miracle or mystery."

Let us turn to a branch of knowledge which deals with certainties up
to the limit of the senses, and is involved in no speculations beyond
them. In certain points of view, HUMAN ANATOMY may be considered an
almost exhausted science. From time to time some small organ which
had escaped earlier observers has been pointed out,--such parts as
the tensor tarsi, the otic ganglion, or the Pacinian bodies; but some
of our best anatomical works are those which have been classic for
many generations. The plates of the bones in Vesalius, three
centuries old, are still masterpieces of accuracy, as of art. The
magnificent work of Albinus on the muscles, published in 1747, is
still supreme in its department, as the constant references of the
most thorough recent treatise on the subject, that of Theile,
sufficiently show. More has been done in unravelling the mysteries
of the fasciae, but there has been a tendency to overdo this kind of
material analysis. Alexander Thomson split them up into cobwebs, as
you may see in the plates to Velpeau's Surgical Anatomy. I well
remember how he used to shake his head over the coarse work of Scarpa
and Astley Cooper,--as if Denner, who painted the separate hairs of
the beard and pores of the skin in his portraits, had spoken lightly
of the pictures of Rubens and Vandyk.

Not only has little been added to the catalogue of parts, but some
things long known had become half-forgotten. Louis and others
confounded the solitary glands of the lower part of the small
intestine with those which "the great Brunner," as Haller calls him,
described in 1687 as being found in the duodenum. The display of the
fibrous structure of the brain seemed a novelty as shown by
Spurzheim. One is startled to find the method anticipated by Raymond
Vieussens nearly two centuries ago. I can hardly think Gordon had
ever looked at his figures, though he names their author, when he
wrote the captious and sneering article which attracted so much
attention in the pages of the "Edinburgh Review."

This is the place, if anywhere, to mention any observations I could
pretend to have made in the course of my teaching the structure of
the human body. I can make no better show than most of my
predecessors in this well-reaped field. The nucleated cells found
connected with the cancellated structure of the bones, which I first
pointed out and had figured in 1847, and have shown yearly from that
time to the present, and the fossa masseterica, a shallow concavity
on the ramus of the lower jaw, for the lodgment of the masseter
muscle, which acquires significance when examined by the side of the
deep cavity on the corresponding part in some carnivora to which it
answers, may perhaps be claimed as deserving attention. I have also
pleased myself by making a special group of the six radiating muscles
which diverge from the spine of the axis, or second cervical
vertebra, and by giving to it the name stella musculosa nuchaee. But
this scanty catalogue is only an evidence that one may teach long and
see little that has not been noted by those who have gone before him.
Of course I do not think it necessary to include rare, but already
described anomalies, such as the episternal bones, the rectus
sternalis, and other interesting exceptional formations I have
encountered, which have shown a curious tendency to present
themselves several times in the same season, perhaps because the
first specimen found calls our attention to any we may subsequently
meet with.

The anatomy of the scalpel and the amphitheatre was, then, becoming
an exhausted branch of investigation. But during the present century
the study of the human body has changed its old aspect, and become
fertile in new observations. This rejuvenescence was effected by
means of two principal agencies,--new methods and a new instrument.

Descriptive anatomy, as known from an early date, is to the body what
geography is to the planet. Now geography was pretty well known so
long ago as when Arrowsmith, who was born in 1750, published his
admirable maps. But in that same year was born Werner, who taught a
new way of studying the earth, since become familiar to us all under
the name of Geology.

What geology has done for our knowledge of the earth, has been done
for our knowledge of the body by that method of study to which is
given the name of General Anatomy. It studies, not the organs as
such, but the elements out of which the organs are constructed. It
is the geology of the body, as that is the general anatomy of the
earth. The extraordinary genius of Bichat, to whom more than any
other we owe this new method of study, does not require Mr. Buckle's
testimony to impress the practitioner with the importance of its
achievements. I have heard a very wise physician question whether
any important result had accrued to practical medicine from Harvey's
discovery of the circulation. But Anatomy, Physiology, and Pathology
have received a new light from this novel method of contemplating the
living structures, which has had a vast influence in enabling the
practitioner at least to distinguish and predict the course of
disease. We know as well what differences to expect in the habits of
a mucous and of a serous membrane, as what mineral substances to look
for in the chalk or the coal measures. You have only to read
Cullen's description of inflammation of the lungs or of the bowels,
and compare it with such as you may find in Laennec or Watson, to see
the immense gain which diagnosis and prognosis have derived from
general anatomy.

The second new method of studying the human structure, beginning with
the labors of Scarpa, Burns, and Colles, grew up principally during
the first third of this century. It does not deal with organs, as
did the earlier anatomists, nor with tissues, after the manner of
Bichat. It maps the whole surface of the body into an arbitrary
number of regions, and studies each region successively from the
surface to the bone, or beneath it. This hardly deserves the name of
a science, although Velpeau has dignified it with that title, but it
furnishes an admirable practical way for the surgeon who has to
operate on a particular region of the body to study that region. If
we are buying a farm, we are not content with the State map or a
geological chart including the estate in question. We demand an
exact survey of that particular property, so that we may know what we
are dealing with. This is just what regional, or, as it is sometimes
called, surgical anatomy, does for the surgeon with reference to the
part on which his skill is to be exercised. It enables him to see
with the mind's eye through the opaque tissues down to the bone on
which they lie, as if the skin were transparent as the cornea, and
the organs it covers translucent as the gelatinous pulp of a medusa.

It is curious that the Japanese should have anticipated Europe in a
kind of rude regional anatomy. I have seen a manikin of Japanese
make traced all over with lines, and points marking their
intersection. By this their doctors are guided in the performance of
acupuncture, marking the safe places to thrust in needles, as we buoy
out our ship-channels, and doubtless indicating to learned eyes the
spots where incautious meddling had led to those little accidents of
shipwreck to which patients are unfortunately liable.

A change of method, then, has given us General and Regional Anatomy.
These, too, have been worked so thoroughly, that, if not exhausted,
they have at least become to a great extent fixed and positive
branches of knowledge. But the first of them, General Anatomy, would
never, have reached this positive condition but for the introduction
of that, instrument which I have mentioned as the second great aid to
modern progress.

This instrument is the achromatic microscope. For the history of the
successive steps by which it became the effective scientific
implement we now possess, I must refer you to the work of Mr.
Quekett, to an excellent article in the "Penny Cyclopaedia," or to
that of Sir David Brewster in the "Encyclopaedia Britannica." It is
a most interesting piece of scientific history, which shows how the
problem which Biot in 1821 pronounced insolvable was in the course of
a few years practically solved, with a success equal to that which
Dollond had long before obtained with the telescope. It is enough
for our purpose that we are now in possession of an instrument freed
from all confusions and illusions, which magnifies a thousand
diameters,--a million times in surface,--without serious distortion
or discoloration of its object.

A quarter of a century ago, or a little more, an instructor would not
have hesitated to put John Bell's "Anatomy" and Bostock's
"Physiology" into a student's hands, as good authority on their
respective subjects. Let us not be unjust to either of these
authors. John Bell is the liveliest medical writer that I can
remember who has written since the days of delightful old Ambroise
Pare. His picturesque descriptions and bold figures are as good now
as they ever were, and his book can never become obsolete. But
listen to what John Bell says of the microscope:

"Philosophers of the last age had been at infinite pains to find the
ultimate fibre of muscles, thinking to discover its properties in its
form; but they saw just in proportion to the glasses which they used,
or to their practice and skill in that art, which is now almost

Dr. Bostock's work, neglected as it is, is one which I value very
highly as a really learned compilation, full of original references.
But Dr. Bostock says: "Much as the naturalist has been indebted to
the microscope, by bringing into view many beings of which he could
not otherwise have ascertained the existence, the physiologist has
not yet derived any great benefit from the instrument."

These are only specimens of the manner in which the microscope and
its results were generally regarded by the generation just preceding
our own.

I have referred you to the proper authorities for the account of
those improvements which about the year 1830 rendered the compound
microscope an efficient and trustworthy instrument. It was now for
the first time that a true general anatomy became possible. As early
as 1816 Treviranus had attempted to resolve the tissues, of which
Bichat had admitted no less than twenty-one, into their simple
microscopic elements. How could such an attempt succeed, Henle well
asks, at a time when the most extensively diffused of all the
tissues, the areolar, was not at all understood? All that method
could do had been accomplished by Bichat and his followers. It was
for the optician to take the next step. The future of anatomy and
physiology, as an enthusiastic micrologist of the time said, was in
the hands of Messrs. Schieck and Pistor, famous opticians of Berlin.

In those earlier days of which I am speaking, all the points of
minute anatomy were involved in obscurity. Some found globules
everywhere, some fibres. Students disputed whether the conjunctiva
extended over the cornea or not, and worried themselves over Gaultier
de Claubry's stratified layers of the skin, or Breschet's
blennogenous and chromatogenous organs. The dartos was a puzzle, the
central spinal canal a myth, the decidua clothed in fable as much as
the golden fleece. The structure of bone, now so beautifully made
out,--even that of the teeth, in which old Leeuwenhoek, peeping with
his octogenarian eyes through the minute lenses wrought with his own
hands, had long ago seen the "pipes," as he called them,--was hardly
known at all. The minute structure of the viscera lay in the mists
of an uncertain microscopic vision. The intimate recesses of the
animal system were to the students of anatomy what the anterior of
Africa long was to geographers, and the stories of microscopic
explorers were as much sneered at as those of Bruce or Du Chailly,
and with better reason.

Now what have we come to in our own day? In the first place, the
minute structure of all the organs has been made out in the most
satisfactory way. The special arrangements of the vessels and the
ducts of all the glands, of the air-tubes and vesicles of the lungs,
of the parts which make up the skin and other membranes, all the
details of those complex parenchymatous organs which had confounded
investigation so long, have been lifted out of the invisible into the
sight of all observers. It is fair to mention here, that we owe a
great deal to the art of minute injection, by which we are enabled to
trace the smallest vessels in the midst of the tissues where they are
distributed. This is an old artifice of anatomists. The famous
Ruysch, who died a hundred and thirty years ago, showed that each of
the viscera has its terminal vessels arranged in its own peculiar
way; the same fact which you may see illustrated in Gerber's figures
after the minute injections of Berres. I hope to show you many
specimens of this kind in the microscope, the work of English and
American hands. Professor Agassiz allows me also to make use of a
very rich collection of injected preparations sent him by Professor
Hyrtl, formerly of Prague, now of Vienna, for the proper exhibition
of which I had a number of microscopes made expressly, by Mr. Grunow,
during the past season. All this illustrates what has been done for
the elucidation of the intimate details of formation of the organs.

But the great triumph of the microscope as applied to anatomy has
been in the resolution of the organs and the tissues into their
simple constituent anatomical elements. It has taken up general
anatomy where Bichat left it. He had succeeded in reducing the
structural language of nature to syllables, if you will permit me to
use so bold an image. The microscopic observers who have come after
him have analyzed these into letters, as we may call them,--the
simple elements by the combination of which Nature spells out
successively tissues, which are her syllables, organs which are her
words, systems which are her chapters, and so goes on from the simple
to the complex, until she binds up in one living whole that wondrous
volume of power and wisdom which we call the human body.

The alphabet of the organization is so short and simple, that I will
risk fatiguing your attention by repeating it, according to the plan
I have long adopted.

A. Cells, either floating, as in the blood, or fixed, like those in
the cancellated structure of bone, already referred to. Very
commonly they have undergone a change of figure, most frequently a
flattening which reduces them to scales, as in the epidermis and the

B. Simple, translucent, homogeneous solid, such as is found at the
back of the cornea, or forming the intercellular substance of

C. The white fibrous element, consisting of very delicate, tenacious
threads. This is the long staple textile substance of the body. It
is to the organism what cotton is pretended to be to our Southern
States. It pervades the whole animal fabric as areolar tissue, which
is the universal packing and wrapping material. It forms the
ligaments which bind the whole frame-work together. It furnishes the
sinews, which are the channels of power. It enfolds every muscle.
It wraps the brain in its hard, insensible folds, and the heart
itself beats in a purse that is made of it.

D. The yellow elastic, fibrous element, the caoutchouc of the animal
mechanism, which pulls things back into place, as the India-rubber
band shuts the door we have opened.

E. The striped muscular fibre,--the red flesh, which shortens itself
in obedience to the will, and thus produces all voluntary active

F. The unstriped muscular fibre, more properly the fusiform-cell
fibre, which carries on the involuntary internal movements.

G. The nerve-cylinder, a glassy tube, with a pith of some firmness,
which conveys sensation to the brain and the principle which induces
motion from it.

H. The nerve-corpuscle, the centre of nervous power.

I. The mucous tissue, as Virchow calls it, common in embryonic
structures, seen in the vitreous humor of the adult.

To these add X, granules, of indeterminate shape and size, Y, for
inorganic matters, such as the salts of bone and teeth, and Z, to
stand as a symbol of the fluids, and you have the letters of what I
have ventured to call the alphabet of the body.

But just as in language certain diphthongs and syllables are
frequently recurring, so we have in the body certain secondary and
tertiary combinations, which we meet more frequently than the
solitary elements of which they are composed.

Thus A B, or a collection of cells united by simple structureless
solid, is seen to be extensively employed in the body under the name
of cartilage. Out of this the surfaces of the articulations and the
springs of the breathing apparatus are formed. But when Nature came
to the buffers of the spinal column (intervertebral disks) and the
washers of the joints (semilunar fibrocartilages of the knee, etc.),
she required more tenacity than common cartilage possessed. What did
she do? What does man do in a similar case of need? I need hardly
tell you. The mason lays his bricks in simple mortar. But the
plasterer works some hair into the mortar which he is going to lay in
large sheets on the walls. The children of Israel complained that
they had no straw to make their bricks with, though portions of it
may still be seen in the crumbling pyramid of Darshour, which they
are said to have built. I visited the old house on Witch Hill in
Salem a year or two ago, and there I found the walls coated with clay
in which straw was abundantly mingled;--the old Judaizing witch-
hangers copied the Israelites in a good many things. The Chinese and
the Corsicans blend the fibres of amianthus in their pottery to give
it tenacity. Now to return to Nature. To make her buffers and
washers hold together in the shocks to which they would be subjected,
she took common cartilage and mingled the white fibrous tissue with
it, to serve the same purpose as the hair in the mortar, the straw in
the bricks and in the plaster of the old wall, and the amianthus in
the earthen vessels. Thus we have the combination A B C, or fibro-
cartilage. Again, the bones were once only gristle or cartilage, A
B. To give them solidity they were infiltrated with stone, in the
form of salts of lime, an inorganic element, so that bone would be
spelt out by the letters A, B, and Y.

If from these organic syllables we proceed to form organic words, we
shall find that Nature employs three principal forms; namely,
Vessels, Membranes, and Parenchyma, or visceral tissue. The most
complex of them can be resolved into a combination of these few
simple anatomical constituents.

Passing for a moment into the domain of PATHOLOGICAL ANATOMY, we find
the same elements in morbid growths that we have met with in normal
structures. The pus-corpuscle and the white blood-corpuscle can only
be distinguished by tracing them to their origin. A frequent form of
so-called malignant disease proves to be only a collection of altered
epithelium-cells. Even cancer itself has no specific anatomical
element, and the diagnosis of a cancerous tumor by the microscope,
though tolerably sure under the eye of an expert, is based upon
accidental, and not essential points,--the crowding together of the
elements, the size of the cell-nuclei, and similar variable

Let us turn to PHYSIOLOGY. The microscope, which has made a new
science of the intimate structure of the organs, has at the same time
cleared up many uncertainties concerning the mechanism of the special
functions. Up to the time of the living generation of observers,
Nature had kept over all her inner workshops the forbidding
inscription, No Admittance! If any prying observer ventured to spy
through his magnifying tubes into the mysteries of her glands and
canals and fluids, she covered up her work in blinding mists and
bewildering halos, as the deities of old concealed their favored
heroes in the moment of danger.

Science has at length sifted the turbid light of her lenses, and
blanched their delusive rainbows.

Anatomy studies the organism in space. Physiology studies it also in
time. After the study of form and composition follows close that of
action, and this leads us along back to the first moment of the germ,
and forward to the resolution of the living frame into its lifeless
elements. In this way Anatomy, or rather that branch of it which we
call Histology, has become inseparably blended with the study of
function. The connection between the science of life and that of
intimate structure on the one hand, and composition on the other, is
illustrated in the titles of two recent works of remarkable
excellence,--"the Physiological Anatomy" of Todd and Bowman, and the
"Physiological Chemistry" of Lehmann.

Let me briefly recapitulate a few of our acquisitions in Physiology,
due in large measure to our new instruments and methods of research,
and at the same time indicate the limits which form the permanent or
the temporary boundaries of our knowledge. I will begin with the
largest fact and with the most absolute and universally encountered

The "largest truth in Physiology" Mr. Paget considers to be "the
development of ova through multiplication and division of their
cells." I would state it more broadly as the agency of the cell in
all living processes. It seems at present necessary to abandon the
original idea of Schwann, that we can observe the building up of a
cell from the simple granules of a blastema, or formative fluid. The
evidence points rather towards the axiom, Omnis cellula a cellula;
that is, the germ of a new cell is always derived from a preexisting
cell. The doctrine of Schwann, as I remarked long ago (1844), runs
parallel with the nebular theory in astronomy, and they may yet stand
or fall together.

As we have seen Nature anticipating the plasterer in fibro-cartilage,
so we see her beforehand with the glassblower in her dealings with
the cell. The artisan blows his vitreous bubbles, large or small, to
be used afterwards as may be wanted. So Nature shapes her hyaline
vesicles and modifies them to serve the needs of the part where they
are found. The artisan whirls his rod, and his glass bubble becomes
a flattened disk, with its bull's-eye for a nucleus. These lips of
ours are all glazed with microscopic tiles formed of flattened cells,
each one of them with its nucleus still as plain and relatively as
prominent, to the eye of the microscopist, as the bull's-eye in the
old-fashioned windowpane. Everywhere we find cells, modified or
unchanged. They roll in inconceivable multitudes (five millions and
more to the cubic millimetre, according to Vierordt) as blood-disks
through our vessels. A close-fitting mail of flattened cells coats
our surface with a panoply of imbricated scales (more than twelve
thousand millions), as Harting has computed, as true a defence against
our enemies as the buckler of the armadillo or the carapace of the
tortoise against theirs. The same little protecting organs pave all
the great highways of the interior system. Cells, again, preside
over the chemical processes which elaborate the living fluids; they
change their form to become the agents of voluntary and involuntary
motion; the soul itself sits on a throne of nucleated cells, and
flashes its mandates through skeins of glassy filaments which once
were simple chains of vesicles. And, as if to reduce the problem of
living force to its simplest expression, we see the yolk of a
transparent egg dividing itself in whole or in part, and again
dividing and subdividing, until it becomes a mass of cells, out of
which the harmonious diversity of the organs arranges itself, worm or
man, as God has willed from the beginning.

This differentiation having been effected, each several part assumes
its special office, having a life of its own adjusted to that of
other parts and the whole. "Just as a tree constitutes a mass
arranged in a definite manner, in which, in every single part, in the
leaves as in the root, in the trunk as in the blossom, cells are
discovered to be the ultimate elements, so is it also with the forms
of animal life. Every animal presents itself as a sum of vital
unities, every one of which manifests all the characteristics of

The mechanism is as clear, as unquestionable, as absolutely settled
and universally accepted, as the order of movement of the heavenly
bodies, which we compute backward to the days of the observatories on
the plains of Shinar, and on the faith of which we regulate the
movements of war and trade by the predictions of our ephemeris.

The mechanism, and that is all. We see the workman and the tools,
but the skill that guides the work and the power that performs it are
as invisible as ever. I fear that not every listener took the
significance of those pregnant words in the passage I quoted from
John Bell,--"thinking to discover its properties in its form." We
have discovered the working bee in this great hive of organization.
We have detected the cell in the very act of forming itself from a
nucleus, of transforming itself into various tissues, of selecting
the elements of various secretions. But why one cell becomes nerve
and another muscle, why one selects bile and another fat, we can no
more pretend to tell, than why one grape sucks out of the soil the
generous juice which princes hoard in their cellars, and another the
wine which it takes three men to drink,--one to pour it down, another
to swallow it, and a third to hold him while it is going down.
Certain analogies between this selecting power and the phenomena of
endosmosis in the elective affinities of chemistry we can find, but
the problem of force remains here, as everywhere, unsolved and

Do we gain anything by attempting to get rid of the idea of a special
vital force because we find certain mutually convertible relations
between forces in the body and out of it? I think not, any more than
we should gain by getting rid of the idea and expression Magnetism
because of its correlation with electricity. We may concede the
unity of all forms of force, but we cannot overlook the fixed
differences of its manifestations according to the conditions under
which it acts. It is a mistake, however, to think the mystery is
greater in an organized body than in any other. We see a stone fall
or a crystal form, and there is nothing stranger left to wonder at,
for we have seen the Infinite in action.

Just so far as we can recognize the ordinary modes of operation of
the common forces of nature,--gravity, cohesion, elasticity,
transudation, chemical action, and the rest,--we see the so-called
vital acts in the light of a larger range of known facts and familiar
analogies. Matteuecci's well-remembered lectures contain many and
striking examples of the working of physical forces in physiological
processes. Wherever rigid experiment carries us, we are safe in
following this lead; but the moment we begin to theorize beyond our
strict observation, we are in danger of falling into those mechanical
follies which true science has long outgrown.

Recognizing the fact, then, that we have learned nothing but the
machinery of life, and are no nearer to its essence, what is it that
we have gained by this great discovery of the cell formation and

It would have been reward enough to learn the method Nature pursues
for its own sake. If the sovereign Artificer lets us into his own
laboratories and workshops, we need not ask more than the privilege
of looking on at his work. We do not know where we now stand in the
hierarchy of created intelligences. We were made a little lower than
the angels. I speak it not irreverently; as the lower animals
surpass man in some of their attributes, so it may be that not every
angel's eye can see as broadly and as deeply into the material works
of God as man himself, looking at the firmament through an equatorial
of fifteen inches' aperture, and searching into the tissues with a
twelfth of an inch objective.

But there are other positive gains of a more practical character.
Thus we are no longer permitted to place the seat of the living
actions in the extreme vessels, which are only the carriers from
which each part takes what it wants by the divine right of the
omnipotent nucleated cell. The organism has become, in the words
already borrowed from Virchow, "a sum of vital unities." The
strictum and laxum, the increased and diminished action of the
vessels, out of which medical theories and methods of treatment have
grown up, have yielded to the doctrine of local cell-communities,
belonging to this or that vascular district, from which they help
themselves, as contractors are wont to do from the national treasury.

I cannot promise to do more than to select a few of the points of
contact between our ignorance and our knowledge which present
particular interest in the existing state of our physiological
acquisitions. Some of them involve the microscopic discoveries of
which I have been speaking, some belong to the domain of chemistry,
and some have relations with other departments of physical science.

If we should begin with the digestive function, we should find that
the long-agitated question of the nature of the acid of the gastric
juice is becoming settled in favor of the lactic. But the whole
solvent agency of the digestive fluid enters into the category of
that exceptional mode of action already familiar to us in chemistry
as catalysis. It is therefore doubly difficult of explanation;
first, as being, like all reactions, a fact not to be accounted for
except by the imaginative appeal to "affinity," and secondly, as
being one of those peculiar reactions provoked by an element which
stands outside and looks on without compromising itself.

The doctrine of Mulder, so widely diffused in popular and scientific
belief, of the existence of a common base of all albuminous
substances, the so-called protein, has not stood the test of rigorous
analysis. The division of food into azotized and non-azotized is no
doubt important, but the attempt to show that the first only is
plastic or nutritive, while the second is simply calorifacient, or
heat-producing, fails entirely in the face of the facts revealed by
the study of man in different climates, and of numerous experiments
in the feeding of animals. I must return to this subject in
connection with the respiratory function.

The sugar-making faculty of the liver is another "catalytic" mystery,
as great as the rest of them, and no greater. Liver-tissue brings
sugar out of the blood, or out of its own substance;--why?

Quia est in eo
Virtus saccharitiva.

Just what becomes of the sugar beyond the fact of its disappearance
before it can get into the general circulation and sweeten our
tempers, it is hard to say.

The pancreatic fluid makes an emulsion of the fat contained in our
food, but just how the fatty particles get into the villi we must
leave Brucke and Kolliker to settle if they can.

No one has shown satisfactorily the process by which the blood-
corpuscles are formed out of the lymph-corpuscles, nor what becomes
of them. These two questions are like those famous household
puzzles,--Where do the flies come from? and, Where do the pins go

There is a series of organs in the body which has long puzzled
physiologists,--organs of glandular aspect, but having no ducts,--the
spleen, the thyroid and thymus bodies, and the suprarenal capsules.
We call them vascular glands, and we believe that they elaborate
colored and uncolored blood-cells; but just what changes they effect,
and just how they effect them, it has proved a very difficult matter
to determine. So of the noted glandules which form Peyer's patches,
their precise office, though seemingly like those of the lymphatic
glands, cannot be positively assigned, so far as I know, at the
present time. It is of obvious interest to learn it with reference
to the pathology of typhoid fever. It will be remarked that the
coincidence of their changes in this disease with enlargement of the
spleen suggests the idea of a similarity of function in these two

The theories of the production of animal heat, from the times of
Black, Lavoisier, and Crawford to those of Liebig, are familiar to
all who have paid any attention to physiological studies. The
simplicity of Liebig's views, and the popular form in which they have
been presented, have given them wide currency, and incorporated them
in the common belief and language of our text-books. Direct
oxidation or combustion of the carbon and hydrogen contained in the
food, or in the tissues themselves; the division of alimentary
substances into respiratory, or non-azotized, and azotized,--these
doctrines are familiar even to the classes in our high-schools. But
this simple statement is boldly questioned. Nothing proves that
oxygen combines (in the system) with hydrogen and carbon in
particular, rather than with sulphur and azote. Such is the well-
grounded statement of Robin and Verdeil. "It is very probable that
animal heat is entirely produced by the chemical actions which take
place in the organism, but the phenomenon is too complex to admit of
our calculating it according to the quality of oxygen consumed."
These last are the words of Regnault, as cited by Mr. Lewes, whose
intelligent discussion of this and many of the most interesting
physiological problems I strongly recommend to your attention.

This single illustration covers a wider ground than the special
function to which it belongs. We are learning that the chemistry of
the body must be studied, not simply by its ingesta and egesta, but
that there is a long intermediate series of changes which must be
investigated in their own light, under their own special conditions.
The expression "sum of vital unities" applies to the chemical
actions, as well as to other actions localized in special parts; and
when the distinguished chemists whom I have just cited entitle their
work a treatise on the immediate principles of the body, they only
indicate the nature of that profound and subtile analysis which must
take the place of all hasty generalizations founded on a comparison
of the food with residual products.

I will only call your attention to the fact, that the exceptional
phenomenon of the laboratory is the prevailing law of the organism.
Nutrition itself is but one great catalytic process. As the blood
travels its rounds, each part selects its appropriate element and
transforms it to its own likeness. Whether the appropriating agent
be cell or nucleus, or a structureless solid like the intercellular
substance of cartilage, the fact of its presence determines the
separation of its proper constituents from the circulating fluid, so
that even when we are wounded bone is replaced by bone, skin by skin,
and nerve by nerve.

It is hardly without a smile that we resuscitate the old question of
the 'vis insita' of the muscular fibre, so famous in the discussions of
Haller and his contemporaries. Speaking generally, I think we may
say that Haller's doctrine is the one now commonly received; namely,
that the muscles contract in virtue of their own inherent endowments.
It is true that Kolliker says no perfectly decisive fact has been
brought forward to prove that the striated muscles contract with.
out having been acted on by nerves. Yet Mr. Bowman's observations on
the contraction of isolated fibres appear decisive enough (unless we
consider them invalidated by Dr. Lionel Beale's recent researches),
tending to show that each elementary fibre is supplied with nerves;
and as to the smooth muscular fibres, we have Virchow's statement
respecting the contractility of those of the umbilical cord, where
there is not a trace of any nerves.

In the investigation of the nervous system, anatomy and physiology
have gone hand in hand. It is very singular that so important, and
seemingly simple, a fact as the connection of the nerve-tubes, at
their origin or in their course, with the nerve-cells, should have so
long remained open to doubt, as you may see that it did by referring
to the very complete work of Sharpey and Quain (edition of 1849), the
histological portion of which is cordially approved by Kolliker

Several most interesting points of the minute anatomy of the nervous
centres have been laboriously and skilfully worked out by a recent
graduate of this Medical School, in a monograph worthy to stand in
line with those of Lockhart Clarke, Stilling, and Schroder van der
Kolk. I have had the privilege of examining and of showing some of
you a number of Dr. Dean's skilful preparations. I have no space to
give even an abstract of his conclusions. I can only refer to his
proof of the fact, that a single cell may send its processes into
several different bundles of nerve-roots, and to his demonstration of
the curved ascending and descending fibres from the posterior
nerveroots, to reach what he has called the longitudinal columns of
the cornea. I must also mention Dr. Dean's exquisite microscopic
photographs from sections of the medulla oblongata, which appear to
me to promise a new development, if not a new epoch, in anatomical

It having been settled that the nerve-tubes can very commonly be
traced directly to the nerve-cells, the object of all the observers
in this department of anatomy is to follow these tubes to their
origin. We have an infinite snarl of telegraph wires, and we may be
reasonably sure, that, if we can follow them up, we shall find each
of them ends in a battery somewhere. One of the most interesting
problems is to find the ganglionic origin of the great nerves of the
medulla oblongata, and this is the end to which, by the aid of the
most delicate sections, colored so as to bring out their details,
mounted so as to be imperishable, magnified by the best instruments,
and now self-recorded in the light of the truth-telling sunbeam, our
fellow-student is making a steady progress in a labor which I think
bids fair to rank with the most valuable contributions to histology
that we have had from this side of the Atlantic.

It is interesting to see how old questions are incidentally settled
in the course of these new investigations. Thus, Mr. Clarke's
dissections, confirmed by preparations of Mr. Dean's which I have
myself examined, placed the fact of the decussation of the pyramids--
denied by Haller, by Morgagni, and even by Stilling--beyond doubt.
So the spinal canal, the existence of which, at least in the adult,
has been so often disputed, appears as a coarse and unequivocal
anatomical fact in many of the preparations referred to.

While these studies of the structure of the cord have been going on,
the ingenious and indefatigable Brown-Sequard has been investigating
the functions of its different parts with equal diligence. The
microscopic anatomists had shown that the ganglionic corpuscles of
the gray matter of the cord are connected with each other by their
processes, as well as with the nerve-roots. M. Brown-Sequard has
proved by numerous experiments that the gray substance transmits
sensitive impressions and muscular stimulation. The oblique
ascending and descending fibres from the posterior nerve-roots,
joining the "longitudinal columns of the cornua," account for the
results of Brown-Sequard's sections of the posterior columns. The
physiological experimenter has also made it evident that the
decussation of the conductors of sensitive impressions has its seat
in the spinal core, and not in the encephalon, as had been supposed.
Not less remarkable than these results are the facts, which I with
others of my audience have had the opportunity of observing, as shown
by M. Brown-Sequard, of the artificial production of epilepsy in
animals by injuring the spinal cord, and the induction of the
paroxysm by pinching a certain portion of the skin. I would also
call the student's attention to his account of the relations of the
nervous centres to nutrition and secretion, the last of which
relations has been made the subject of an extended essay by our
fellow countryman, Dr. H. F. Campbell of Georgia.

The physiology of the spinal cord seems a simple matter as you study
it in Longet. The experiments of Brown-Sequard have shown the
problem to be a complex one, and raised almost as many doubts as they
have solved questions; at any rate, I believe all lecturers on
physiology agree that there is no part of their task they dread so
much as the analysis of the evidence relating to the special offices
of the different portions of the medulla spinalis. In the brain we
are sure that we do not know how to localize functions; in the spinal
cord, we think we do know something; but there are so many anomalies,
and seeming contradictions, and sources of fallacy, that beyond the
facts of crossed paralysis of sensation, and the conducting agency of
the gray substance, I am afraid we retain no cardinal principles
discovered since the development of the reflex function took its
place by Sir Charles Bell's great discovery.

By the manner in which I spoke of the brain, you will see that I am
obliged to leave phrenology sub Jove,--out in the cold,--as not one
of the household of science. I am not one of its haters; on the
contrary, I am grateful for the incidental good it has done. I love
to amuse myself in its plaster Golgothas, and listen to the glib
professor, as he discovers by his manipulations

"All that disgraced my betters met in me."

I loved of old to see square-headed, heavy-jawed Spurzheim make a
brain flower out into a corolla of marrowy filaments, as Vieussens
had done before him, and to hear the dry-fibred but human-hearted
George Combe teach good sense under the disguise of his equivocal
system. But the pseudo-sciences, phrenology and the rest, seem to me
only appeals to weak minds and the weak points of strong ones. There
is a pica or false appetite in many intelligences; they take to odd
fancies in place of wholesome truth, as girls gnaw at chalk and
charcoal. Phrenology juggles with nature. It is so adjusted as to
soak up all evidence that helps it, and shed all that harms it. It
crawls forward in all weathers, like Richard Edgeworth's hygrometer.
It does not stand at the boundary of our ignorance, it seems to me,
but is one of the will-o'-the-wisps of its undisputed central domain
of bog and quicksand. Yet I should not have devoted so many words to
it, did I not recognize the light it has thrown on human actions by
its study of congenital organic tendencies. Its maps of the.
surface of the head are, I feel sure, founded on a delusion, but its
studies of individual character are always interesting and

The "snapping-turtle" strikes after its natural fashion when it first
comes out of the egg. Children betray their tendencies in their way
of dealing with the breasts that nourish them; nay, lean venture to
affirm, that long before they are born they teach their mothers
something of their turbulent or quiet tempers.

"Castor gaudet equis, ovo proanatus eodem

Strike out the false pretensions of phrenology; call it anthropology;
let it study man the individual in distinction from man the
abstraction, the metaphysical or theological lay-figure; and it
becomes "the proper study of mankind," one of the noblest and most
interesting of pursuits.

The whole physiology of the nervous system, from the simplest
manifestation of its power in an insect up to the supreme act of the
human intelligence working through the brain, is full of the most
difficult yet profoundly interesting questions. The singular
relations between electricity and nerve-force, relations which it has
been attempted to interpret as meaning identity, in the face of
palpable differences, require still more extended studies. You may
be interested by Professor Faraday's statement of his opinion on the
matter. "Though I am not satisfied that the nervous fluid is only
electricity, still I think that the agent in the nervous system maybe
an inorganic force; and if there be reason for supposing that
magnetism is a higher relation of force than electricity, so it may
well be imagined that the nervous power may be of a still more
exalted character, and yet within the reach of experiment."

In connection with this statement, it is interesting to refer to the
experiments of Helmholtz on the rapidity of transmission of the
nervous actions. The rate is given differently in Valentin's report
of these experiments and in that found in the "Scientific Annual" for
1858. One hundred and eighty to three hundred feet per second is the
rate of movement assigned for sensation, but all such results must be
very vaguely approximative. Boxers, fencers, players at the Italian
game of morn, "prestidigitators," and all who depend for their
success on rapidity of motion, know what differences there are in the
personal equation of movement.

Reflex action, the mechanical sympathy, if I may so call it, of
distant parts; Instinct, which is crystallized intelligence,--an
absolute law with its invariable planes and angles introduced into
the sphere of consciousness, as raphides are inclosed in the living
cells of plants; Intellect,--the operation of the thinking principle
through material organs, with an appreciable waste of tissue in every
act of thought, so that our clergymen's blood has more phosphates to
get rid of on Monday than on any other day of the week; Will,--
theoretically the absolute determining power, practically limited in
different degrees by the varying organization of races and
individuals, annulled or perverted by different ill-understood
organic changes; on all these subjects our knowledge is in its
infancy, and from the study of some of them the interdict of the
Vatican is hardly yet removed.

I must allude to one or two points in the histology and physiology of
the organs of sense. The anterior continuation of the retina beyond
the ora serrata has been a subject of much discussion. If H. Muller
and Kolliker can be relied upon, this question is settled by
recognizing that a layer of cells, continued from the retina, passes
over the surface of the zonula Zinnii, but that no proper nervous
element is so prolonged forward.

I observe that Kolliker calls the true nervous elements of the retina
"the layer of gray cerebral substance." In fact, the ganglionic
corpuscles of each eye may be considered as constituting a little
brain, connected with the masses behind by the commissure, commonly
called the optic nerve. We are prepared, therefore, to find these
two little brains in the most intimate relations with each other, as
we find the cerebral hemispheres. We know that they are directly
connected by fibres that arch round through the chiasma.

I mention these anatomical facts to introduce a physiological
observation of my own, first announced in one of the lectures before
the Medical Class, subsequently communicated to the American Academy
of Arts and Sciences, and printed in its "Transactions" for February
14, 1860. I refer to the apparent transfer of impressions from one
retina to the other, to which I have given the name reflex vision.
The idea was suggested to me in consequence of certain effects
noticed in employing the stereoscope. Professor William B. Rodgers
has since called the attention of the American Scientific Association
to some facts bearing on the subject, and to a very curious
experiment of Leonardo da Vinci's, which enables the observer to look
through the palm of his hand (or seem to), as if it had a hole bored
through it. As he and others hesitated to accept my explanation, I
was not sorry to find recently the following words in the
"Observations on Man" of that acute observer and thinker, David
Hartley. "An impression made on the right eye alone by a single
object may propagate itself into the left, and there raise up an
image almost equal in vividness to itself; and consequently when we
see with one eye only, we may, however, have pictures in both eyes."
Hartley, in 1784, had anticipated many of the doctrines which have
since been systematized into the theory of reflex actions, and with
which I have attempted to associate this act of reflex vision. My
sixth experiment, however, in the communication referred to, appears
to me to be a crucial one, proving the correctness of my explanation,
and I am not aware that it has been before instituted.

Another point of great interest connected with the physiology of
vision, and involved for a long time in great obscurity, is that of
the adjustment of the eye to different distances. Dr. Clay Wallace
of New York, who published a very ingenious little book on the eye
about twenty years ago, with vignettes reminding one of Bewick, was
among the first, if not the first, to describe the ciliary muscle, to
which the power of adjustment is generally ascribed. It is
ascertained, by exact experiment with the phacueidoscope, that
accommodation depends on change of form of the crystalline lens.
Where the crystalline is wanting, as Mr. Ware long ago taught, no
power of accommodation remains. The ciliary muscle is generally
thought to effect the change of form of the crystalline. The power
of accommodation is lost after the application of atropine, in
consequence, as is supposed, of the paralysis of this muscle. This,
I believe, is the nearest approach to a demonstration we have on this

I have only time briefly to refer to Professor Draper's most
ingenious theory as to the photographic nature of vision, for an
account of which I must refer to his original and interesting
Treatise on Physiology.

It were to be wished that the elaborate and very interesting
researches of the Marquis Corti, which have revealed such singular
complexity of structure in the cochlea of the ear, had done more to
clear up its doubtful physiology; but I am afraid we have nothing but
hypotheses for the special part it plays in the act of hearing, and
that we must say the same respecting the office of the semicircular

The microscope has achieved some of its greatest triumphs in teaching
us the changes which occur in the development of the embryo. No more
interesting discovery stands recorded in the voluminous literature of
this subject than the one originally announced by Martin Barry,
afterwards discredited, and still later confirmed by Mr. Newport and
others; namely the fact that the fertilizing filament reaches the
interior of the ovum in various animals;--a striking parallel to the
action of the pollen-tube in the vegetable. But beyond the
mechanical facts all is mystery in the movements of organization, as
profound as in the fall of a stone or the formation of a crystal.

To the chemist and the microscopist the living body presents the same
difficulties, arising from the fact that everything is in perpetual
change in the organism. The fibrine of the blood puzzles the one as
much as its globules puzzle the other. The difference between the
branches of science which deal with space only, and those which deal
with space and time, is this: we have no glasses that can magnify
time. The figure I here show you a was photographed from an object
(pleurosigma angulatum) magnified a thousand diameters, or presenting
a million times its natural surface. This other figure of the same
object, enlarged from the one just shown, is magnified seven thousand
diameters, or forty-nine million times in surface. When we can make
the forty-nine millionth of a second as long as its integer,
physiology and chemistry will approach nearer the completeness of

Our reverence becomes more worthy, or, if you will, less unworthy of
its Infinite Object in proportion as our intelligence is lifted and
expanded to a higher and broader understanding of the Divine methods
of action. If Galen called his heathen readers to admire, the power,
the wisdom, the providence, the goodness of the "Framer of the animal
body,"--if Mr. Boyle, the student of nature, as Addison and that
friend of his who had known him for forty years tell us, never
uttered the name of the Supreme Being without making a distinct pause
in his speech, in token of his devout recognition of its awful
meaning,--surely we, who inherit the accumulated wisdom of nearly two
hundred years since the time of the British philosopher, and of
almost two thousand since the Greek physician, may well lift our
thoughts from the works we study to their great Artificer. These
wonderful discoveries which we owe to that mighty little instrument,
the telescope of the inner firmament with all its included worlds;
these simple formulae by which we condense the observations of a
generation in a single axiom; these logical analyses by which we
fence out the ignorance we cannot reclaim, and fix the limits of our
knowledge,--all lead us up to the inspiration of the Almighty, which
gives understanding to the world's great teachers. To fear science
or knowledge, lest it disturb our old beliefs, is to fear the influx
of the Divine wisdom into the souls of our fellow-men; for what is
science but the piecemeal revelation,--uncovering,--of the plan of
creation, by the agency of those chosen prophets of nature whom God
has illuminated from the central light of truth for that single

The studies which we have glanced at are preliminary in your
education to the practical arts which make use of them,--the arts of
healing,--surgery and medicine. The more you examine the structure
of the organs and the laws of life, the more you will find how
resolutely each of the cell-republics which make up the E pluribus
unum of the body maintains its independence. Guard it, feed it, air
it, warm it, exercise or rest it properly, and the working elements
will do their best to keep well or to get well. What do we do with
ailing vegetables? Dr. Warren, my honored predecessor in this chair,
bought a country-place, including half of an old orchard. A few
years afterwards I saw the trees on his side of the fence looking in
good health, while those on the other side were scraggy and
miserable. How do you suppose this change was brought about? By
watering them with Fowler's solution? By digging in calomel freely
about their roots? Not at all; but by loosening the soil round them,
and supplying them with the right kind of food in fitting quantities.

Now a man is not a plant, or, at least, he is a very curious one, for
he carries his soil in his stomach, which is a kind--of portable
flower-pot, and he grows round it, instead of out of it. He has,
besides, a singularly complex nutritive apparatus and a nervous
system. But recollect the doctrine already enunciated in the
language of Virchow, that an animal, like a tree, is a sum of vital
unities, of which the cell is the ultimate element. Every healthy
cell, whether in a vegetable or an animal, necessarily performs its
function properly so long as it is supplied with its proper materials
and stimuli. A cell may, it is true, be congenitally defective, in
which case disease is, so to speak, its normal state. But if
originally sound and subsequently diseased, there has certainly been
some excess, deficiency, or wrong quality in the materials or stimuli
applied to it. You remove this injurious influence and substitute a
normal one; remove the baked coal-ashes, for instance, from the roots
of a tree, and replace them with loam; take away the salt meat from
the patient's table, and replace it with fresh meat and vegetables,
and the cells of the tree or the man return to their duty.

I do not know that we ever apply to a plant any element which is not
a natural constituent of the vegetable structure, except perhaps
externally, for the accidental purpose of killing parasites. The
whole art of cultivation consists in learning the proper food and
conditions of plants, and supplying them. We give them water,
earths, salts of various kinds such as they are made of, with a
chance to help themselves to air and light. The farmer would be
laughed at who undertook to manure his fields or his trees with a
salt of lead or of arsenic. These elements are not constituents of
healthy plants. The gardener uses the waste of the arsenic furnaces
to kill the weeds in his walks.

If the law of the animal cell, and of the animal organism, which is
built up of such cells, is like that of the vegetable, we might
expect that we should treat all morbid conditions of any of the vital
unities belonging to an animal in the same way, by increasing,
diminishing, or changing its natural food or stimuli.

That is an aliment which nourishes; whatever we find in the
organism, as a constant and integral element, either forming part of
its structure, or one of the conditions of vital processes, that and
that only deserves the name of aliment. I see no reason,
therefore, why iron, phosphate of lime, sulphur, should not be
considered food for man, as much as guano or poudrette for
vegetables. Whether one or another of them is best in any given
case,--whether they shall be taken alone or in combination, in large
or small quantities, are separate questions. But they are elements
belonging to the body, and even in moderate excess will produce
little disturbance. There is no presumption against any of this
class of substances, any more than against water or salt, provided
they are used in fitting combinations, proportions, and forms.

But when it comes to substances alien to the healthy system, which
never belong to it as normal constituents, the case is very
different. There is a presumption against putting lead or arsenic
into the human body, as against putting them into plants, because
they do not belong there, any more than pounded glass, which, it is
said, used to be given as a poison. The same thing is true of
mercury and silver. What becomes of these alien substances after
they get into the system we cannot always tell. But in the case of
silver, from the accident of its changing color under the influence
of light, we do know what happens. It is thrown out, in part at
least, under the epidermis, and there it remains to the patient's
dying day. This is a striking illustration of the difficulty which
the system finds in dealing with non-assimilable elements, and
justifies in some measure the vulgar prejudice against mineral

I trust the youngest student on these benches will not commit the
childish error of confounding a presumption against a particular
class of agents with a condemnation of them. Mercury, for instance,
is alien to the system, and eminently disturbing in its influence.
Yet its efficacy in certain forms of specific disease is acknowledged
by all but the most sceptical theorists. Even the esprit moqueur of
Ricord, the Voltaire of pelvic literature, submits to the time-
honored constitutional authority of this great panacea in the class
of cases to which he has devoted his brilliant intelligence. Still,
there is no telling what evils have arisen from the abuse of this
mineral. Dr. Armstrong long ago pointed out some of them, and they
have become matters of common notoriety. I am pleased, therefore,
when I find so able and experienced a practitioner as Dr. Williams of
this city proving that iritis is best treated without mercury, and
Dr. Vanderpoel showing the same thing to be true for pericarditis.

Whatever elements nature does not introduce into vegetables, the
natural food of all animal life,--directly of herbivorous, indirectly
of carnivorous animals,--are to be regarded with suspicion. Arsenic-
eating may seem to improve the condition of horses for a time,--and
even of human beings, if Tschudi's stories can be trusted,--but it
soon appears that its alien qualities are at war with the animal
organization. So of copper, antimony, and other non-alimentary
simple substances; everyone of them is an intruder in the living
system, as much as a constable would be, quartered in our household.
This does not mean that they may not, any of them, be called in for a
special need, as we send for the constable when we have good reason
to think we have a thief under our roof; but a man's body is his
castle, as well as his house, and the presumption is that we are to
keep our alimentary doors bolted against these perturbing agents.

Now the feeling is very apt to be just contrary to this. The habit
has been very general with well-taught practitioners, to have
recourse to the introduction of these alien elements into the system
on the occasion of any slight disturbance. The tongue was a little
coated, and mercury must be given; the skin was a little dry, and the
patient must take antimony. It was like sending for the constable
and the posse comitatus when there is only a carpet to shake or a
refuse-barrel to empty. [Dr. James Johnson advises persons not ailing
to take five grains of blue pill with one or two of aloes twice a
week for three or four months in the year, with half a pint of
compound decoction of sarsaparilla every day for the same period, to
preserve health and prolong life. Pract. Treatise on Dis. of
Liver, etc. p. 272.] The constitution bears slow poisoning a great
deal better than might be expected; yet the most intelligent men in
the profession have gradually got out of the habit of prescribing
these powerful alien substances in the old routine way. Mr. Metcalf
will tell you how much more sparingly they are given by our
practitioners at the present time, than when he first inaugurated the
new era of pharmacy among us. Still, the presumption in favor of
poisoning out every spontaneous reaction of outraged nature is not
extinct in those who are trusted with the lives of their fellow-
citizens. "On examining the file of prescriptions at the hospital, I
discovered that they were rudely written, and indicated a treatment,
as they consisted chiefly of tartar emetic, ipecacuanha, and epsom
salts, hardly favorable to the cure of the prevailing diarrhoea and
dysenteries." In a report of a poisoning case now on trial, where
we are told that arsenic enough was found in the stomach to produce
death in twenty-four hours, the patient is said to have been treated
by arsenic, phosphorus, bryonia, aconite, nux vomica, and muriatic
acid,--by a practitioner of what school it may be imagined.

The traditional idea of always poisoning out disease, as we smoke out
vermin, is now seeking its last refuge behind the wooden cannon and
painted port-holes of that unblushing system of false scientific
pretences which I do not care to name in a discourse addressed to an
audience devoted to the study of the laws of nature in the light of
the laws of evidence. It is extraordinary to observe that the system
which, by its reducing medicine to a name and a farce, has accustomed
all who have sense enough to see through its thin artifices to the
idea that diseases get well without being "cured," should now be the
main support of the tottering poison-cure doctrine. It has
unquestionably helped to teach wise people that nature heals most
diseases without help from pharmaceutic art, but it continues to
persuade fools that art can arrest them all with its specifics.

It is worse than useless to attempt in any way to check the freest
expression of opinion as to the efficacy of any or all of the
"heroic" means of treatment employed by practitioners of different
schools and periods. Medical experience is a great thing, but we
must not forget that there is a higher experience, which tries its
results in a court of a still larger jurisdiction; that, namely, in
which the laws of human belief are summoned to the witness-box, and
obliged to testify to the sources of error which beset the medical
practitioner. The verdict is as old as the father of medicine, who
announces it in the words, "judgment is difficult." Physicians
differed so in his time, that some denied that there was any such
thing as an art of medicine.

One man's best remedies were held as mischievous by another. The art
of healing was like soothsaying, so the common people said; "the same
bird was lucky or unlucky, according as he flew to the right or

The practice of medicine has undergone great changes within the
period of my own observation. Venesection, for instance, has so far
gone out of fashion, that, as I am told by residents of the New York
Bellevue and the Massachusetts General Hospitals, it is almost
obsolete in these institutions, at least in medical practice. The
old Brunonian stimulating treatment has come into vogue again in the
practice of Dr. Todd and his followers. The compounds of mercury
have yielded their place as drugs of all work, and specifics for that
very frequent subjective complaint, nescio quid faciam,--to compounds
of iodine. [Sir Astley Cooper has the boldness,--or honesty,--to
speak of medicines which "are given as much to assist the medical man
as his patient." Lectures (London, 1832), p. 14.] Opium is believed
in, and quinine, and "rum," using that expressive monosyllable to
mean all alcoholic cordials. If Moliere were writing now, instead of
saignare, purgare, and the other, he would be more like to say,
Stimulare, opium dare et potassio-iodizare.

I have been in relation successively with the English and American
evacuant and alterative practice, in which calomel and antimony
figured so largely that, as you may see in Dr. Jackson's last
"Letter," Dr. Holyoke, a good representative of sterling old-
fashioned medical art, counted them with opium and Peruvian bark as
his chief remedies; with the moderately expectant practice of Louis;
the blood-letting "coup sur coup" of Bouillaud; the contra-stimulant
method of Rasori and his followers; the anti-irritant system of
Broussais, with its leeching and gum-water; I have heard from our own
students of the simple opium practice of the renowned German teacher,
Oppolzer; and now I find the medical community brought round by the
revolving cycle of opinion to that same old plan of treatment which
John Brown taught in Edinburgh in the last quarter of the last
century, and Miner and Tully fiercely advocated among ourselves in
the early years of the present. The worthy physicians last
mentioned, and their antagonist Dr. Gallup, used stronger language
than we of these degenerate days permit ourselves. "The lancet is a
weapon which annually slays more than the sword," says Dr. Tully.
"It is probable that, for forty years past, opium and its
preparations have done seven times the injury they have rendered
benefit, on the great scale of the world," says Dr. Gallup.

What is the meaning of these perpetual changes and conflicts of
medical opinion and practice, from an early antiquity to our own
time? Simply this: all "methods" of treatment end in disappointment
of those extravagant expectations which men are wont to entertain of
medical art. The bills of mortality are more obviously affected by
drainage, than by this or that method of practice. The insurance
companies do not commonly charge a different percentage on the lives
of the patients of this or that physician. In the course of a
generation, more or less, physicians themselves are liable to get
tired of a practice which has so little effect upon the average
movement of vital decomposition. Then they are ready for a change,
even if it were back again to a method which has already been tried,
and found wanting.

Our practitioners, or many of them, have got back to the ways of old
Dr. Samuel Danforth, who, as it is well known, had strong objections
to the use of the lancet. By and by a new reputation will be made by

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