of the poison of the rattlesnake or jararaca. The serum that is an
antidote as regards the colubrines. The animal that is immune to the
bite of one may not be immune to the bite of the other. The bite of a
cobra or other colubrine poisonous snake is more painful in its
immediate effects than is the bite of one of the big vipers. The
victim suffers more. There is a greater effect on the nerve-centres,
but less swelling of the wound itself, and, whereas the blood of the
rattlesnake's victim coagulates, the blood of the victim of an elapine
snake--that is, of one of the only poisonous American colubrines--
becomes watery and incapable of coagulation.

Snakes are highly specialized in every way, including their prey. Some
live exclusively on warm-blooded animals, on mammals, or birds. Some
live exclusively on batrachians, others only on lizards, a few only on
insects. A very few species live exclusively on other snakes. These
include one very formidable venomous snake, the Indian hamadryad, or
giant cobra, and several non-poisonous snakes. In Africa I killed a
small cobra which contained within it a snake but a few inches shorter
than itself; but, as far as I could find out, snakes were not the
habitual diet of the African cobras.

The poisonous snakes use their venom to kill their victims, and also
to kill any possible foe which they think menaces them. Some of them
are good-tempered, and only fight if injured or seriously alarmed.
Others are excessively irritable, and on rare occasions will even
attack of their own accord when entirely unprovoked and unthreatened.

On reaching Sao Paulo on our southward journey from Rio to Montevideo,
we drove out to the "Instituto Serumtherapico," designed for the study
of the effects of the venom of poisonous Brazilian snakes. Its
director is Doctor Vital Brazil, who has performed a most
extraordinary work and whose experiments and investigations are not
only of the utmost value to Brazil but will ultimately be recognized
as of the utmost value for humanity at large. I know of no institution
of similar kind anywhere. It has a fine modern building, with all the
best appliances, in which experiments are carried on with all kinds of
serpents, living and dead, with the object of discovering all the
properties of their several kinds of venom, and of developing various
anti-venom serums which nullify the effects of the different venoms.
Every effort is made to teach the people at large by