to draw back on its approach. At last one is
taken, the leathern strap is drawn tight around
his neck by pulling the cord, and is kept so
near to the head that he cannot turn to bite the
stick, if the pressure should provoke his wrath.
Thus secured, we lift him from his dozen of
friends, and, holding the noose firm, so as to
keep him well squeezed against the end of the
stick, we put him on a table. Next, resigning
the staff and string to an assistant, we open
the snake's mouth, and, with the edge of a little
saucer, catch and elevate the two fangs. This
is an old snake, milked often before, and now
declining to bite unless compelled. Holding
the saucer in one hand we seize the snake's
head over the venom gland, and, with a thumb
and forefinger, press the venom forward through
the duct. Suddenly a clear yellow fluid flows
out of the fangs. This is the venom. The
snake is four feet long, untouched for two weeks,
and has given us about twenty drops of poison.
The assistant replaces him in his cage, and we
turn to look at the famous poison which a
living animal carries unharmed in his tissues for
the deadly hurting of whom it may concern.
There is some of this fluid in a phial on the
table before me, and here some of it dried for
three years—a scaly, yellow, shining matter,
like dried white of egg, and as good to kill as
ever it was. No smell, if fresh; no taste;
faintly acid, and chemically a substance which
is so nearly like this very white of egg that no
chemical difference may be made between them.
Two things so alike and so unlike! Indeed, it
seems hardly fair of Nature to set us such
problems. We fall back upon an imagined
difference in the molecular composition of the two
—very consoling, no doubt; but, after all, the
thing is bewildering, explain it as we may. We
would like not to believe it. We think of
poisons as unlike what they hurt. Let us take
from a dog's veins a little blood, keep it a few
hours in the open air, and throw it back into
his circulation, and very surely you have given
him his death. Ugly facts of disease, where the
body gets up its own poisons for home use,
make the wonder less to the doctor; but even
now to him it must still seem wonderful, this
little bit of white of egg to nourish, and this,
to no human test differing in composition, good
for destroying alone.

It was once thought that the poison ceased
to be such when not injected by the maker.
Fontana disproved this, and so we may safely
use it in our researches as we get it from the
snake, with the great advantage of knowing
what dose we administer. Let us now study
the symptoms which this poison produces, and
then learn, if possible, how it acts, and on what
organs; because, as modern science has shown,
all poisons have their especial organs, or sets of
organs, upon which chiefly their destructive
influence falls. This sort of analytic separation
of the effects of poisons is always difficult, and
never more so than as regards venom.

Rattlesnake poison is not fatal to all life.
You cannot kill a crotalus with its own venom,
nor with that of another. Neither can you
poison a plant with venom. And, in fact, if you
manage the experiment cleverly, canary-seed
may be made to sprout from a mixture of venom
and water.

We have seen, too, that the serpent often
swallows his own poison. As for him, if it will
not hurt being put under his skin, the wonder
of its not injuring him when swallowed is little
enough. It only excites amazement when we
learn that it poisons no creature if ingested.
We have fed pigeons with it, day after day, in
doses each enough to have killed forty had it
been put within the tissues. Placed in the
stomach, it lies within some thousandths of an
inch of the blood-vessels, only a thinnest mucous
membrane between; and here it is harmless,
and there it means death. Let us follow this
problem, as has lately been done. Why does it
not poison? We give a pigeon fifty drops of
venom, which, otherwise used, would kill a
hundred, and that surely. For three days we collect
all the excretæ, and then, killing the bird,
remove with care the contents of the intestinal
canal. Knowing well what fluids dissolve the
venom, we separate by this means whatever
poison may be present from all the rest of the
substances passed by or taken from the bird.
Then, with the fluid thus obtained, we inject
the tissues of pigeons. No injury follows; our
poison has gone. But where, and how? Let
us mix a little of it with gastric juice, and keep
it at body-heat for an hour. It still poisons;
but we learn at length, after many essays, that
very long digesting of it in constantly added
quantities of gastric juice does change it
somewhat; and so, as we do not find it in the
excretæ, we come to think that, being what we
call an albuminoid, it is very likely to be altered
during digestion, and so rendered innocent
enough, it may be. Here, at last, we must rest,
having learned, first, that venom will not pass
through the mucous surfaces; and, second, that
it undergoes such change in digestion as to make
it harmless. In these peculiarities it stands
alone, if we except certain putrefying substances
which may usually be swallowed without injury,
but slowly kill if placed under the skin.

As regards also the mode in which venom is
hurtful to animal life, this potent agent is altogether
peculiar. Let us examine a single case. We
inject through a hollow needle two drops of
venom under the skin of a pigeon. On a
sudden, within a minute, it is dead, without pang
or struggle; and the tissues, when examined,
reveal no cause of death. The fatal result is
rarely so speedy; but here, as with all poisons,
personal peculiarities count for a good deal, and
one animal will die in a minute from a dose
which another may resist for hours. We repeat
the experiment, using only half a drop. In a
few minutes the bird staggers, and at last
crouches, too feeble to walk. The feebleness
increases, vomiting occurs, the breathing
becomes laboured, the head falls, a slight convulsion
follows, and the pigeon is dead. This is
all we see—merely a strange intense weakness.