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Scientific American Supplement, No. 303 by Various

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will not produce on the three men either drunkenness at the same moment,
or intoxication at all. Mulattoes can sustain more drastic aperients
than other races; the negro does not suffer from yellow fever, but he
readily falls to phthisis; he will catch the cholera more quickly than a
white. Human races, where they may catch the same intermittent fever at
the identical moment and in the same swamp, will not the less display
different types of fever. Dr. Crevaux has shown that a certain insect
with the North American Indian is not the same as with the negro or the
maroon, and both differ from that peculiar to Europeans.

M. Pasteur's beautiful experiments have conclusively demonstrated that
fowls do not catch the _charbon_; now the vital warmth of birds is from
seven to nine degrees higher than in the case of mammiferous animals;
he imagined that if the fowl was cooled down by baths to the lower
temperature, it would be liable equally to become affected; he tried,
and the result proved he was correct.

The absence, then, of a certain temperature would be the reason why
birds are exempt. The microbes are the agents of infectious disease;
when these swarm in the blood of an individual they seem to leave there
something pernicious for parasites resembling themselves, or to bring
away with them something necessary to the life of their successors. A
glass of sugar and water, where leaven has already fermented and yielded
alcohol, is incapable of producing a second crop of leaven; similarly
the blood of an individual, once contaminated, becomes uninhabitable
afterward for like microbes. The individual has acquired immunity. Such
is the principle of vaccination.--_Paris Correspondent of the Kansas
City Review_.

* * * * *


It has been observed by experienced horse trainers that naturally
vicious horses are rare, and that among those that are properly trained
and kindly treated when colts they are the exception.

It is superfluous to say that a gentle and docile horse is always the
more valuable, other qualities being equal, and it is almost obvious
that gentle treatment tends to develop this admirable quality in the
horse as well as in the human species, while harsh treatment has the
contrary tendency. Horses have been trained so as to be entirely
governed by the words of his driver, and they will obey and perform
their simple but important duties with as much alacrity as the child
obeys the direction of the parent.

It is true that all horses are not equally intelligent and tractable,
but it is probable that there is less difference among them in this
regard than there is among his human masters, since there are many
incitements and ambitions among men that do not affect animals.

The horse learns to know and to have confidence in a gentle driver, and
soon discovers how to secure for himself that which he desires, and
to understand his surroundings and his duties. The tone, volume, and
inflection of his master's voice indicate much, perhaps more than the
words that are spoken. Soothing tones rather than words calm him if
excited by fear or anger, and angry and excited tones tend to excite or
anger him. In short, bad masters make bad horses.

* * * * *

A catalogue, containing brief notices of many important scientific
papers heretofore published in the SUPPLEMENT, may be had gratis at this

* * * * *




Sent by mail, postage prepaid, to subscribers in any part of the United
States or Canada. Six dollars a year, sent, prepaid, to any foreign

All the back numbers of THE SUPPLEMENT, from the commencement, January
1, 1876, can be had. Price, 10 cents each.

All the back volumes of THE SUPPLEMENT can likewise be supplied. Two
volumes are issued yearly. Price of each volume, $2.50, stitched in
paper, or $3.50, bound in stiff covers.

SCIENTIFIC AMERICAN SUPPLEMENT, one year, postpaid, $7.00.

A liberal discount to booksellers, news agents, and canvassers.



* * * * *


In connection with the SCIENTIFIC AMERICAN, Messrs. MUNN & Co. are
Solicitors of American and Foreign Patents, have had 35 years'
experience, and now have the largest establishment in the world. Patents
are obtained on the best terms.

A special notice is made in the SCIENTIFIC AMERICAN of all Inventions
patented through this Agency, with the name and residence of the
Patentee. By the immense circulation thus given, public attention is
directed to the merits of the new patent, and sales or introduction
often easily effected.

Any person who has made a new discovery or invention can ascertain, free
of charge, whether a patent can probably be obtained, by writing to MUNN
& Co.

We also send free our Hand Book about the Patent Laws, Patents, Caveats.
Trade Marks, their costs, and how procured, with hints for procuring
advances on inventions. Address


Branch Office, cor. F and 7th Sts., Washington, D. C.

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