Before trying to explain it, we shall do well to
watch that which takes place when a larger
animal, surviving the first effects, perishes after
a few hours or days. Here is a record of such
a case. A large dog, poisoned with five drops
of venom, lives over the first few hours of
feebleness, and then begins to show a new set
of symptoms. Some horrible malady of the
blood and tissues has come upon him, so that
the vital fluid leaks from the kidneys or
the bowels, and oozes from the gums. The
fang-wounds bleed, and a prick of a needle will
drip blood for hours. Thus exhausted, he dies,
or slowly recovers. Meanwhile, the wound
made by the injecting needle or the fang has
undergone a series of changes, which, rightly
studied, gave the first clue to the true explanation
of how this hideous agent acts.

A large and growing tumour marks where the
needle entered. We cut into it. There is no
inflammation at first; the whole mass is fluid
blood, which by and by soaks every tissue in
the neighbourhood, and even stains the bones
themselves. If, for the sake of contrast, we
wound any healthy part with a common needle,
without venom, we open thus a few small blood-
vessels, which presently cease to bleed, because
the escaped blood quickly clots, and so corks
their open mouths by a rarely failing providence
of all-thoughtful Nature. The conclusion seems
easy, that the venom destroys the power of the
blood to clot, and so deprives the animal of this
exquisite protection against hæmorrhage. If
the creature live long and the dose be heavy,
the collected blood putrefies, abscesses form,
and more or less of the tissue becomes
gangrenous. Nor is this evil only local. The
venom absorbed from the wound enters the
circulation, and soon the whole mass of the blood
has lost power to clot when drawn. We are
not willing to assert that this is a putrefactive
change; but it is certainly in that direction,
because this blood, if drawn, will now decay
faster than other blood. By and by it begins to
leak through the various tissues, and we find
blood escaped out of the vessels and into the
brain, lungs, or intestinal walls, giving in each
case specific symptoms, according to the part
injured and the function disturbed.

A further step has of late been gained towards
comprehending this intricate problem. A young
rabbit was made senseless and motionless with
chloroform. Then its abdomen was opened,
and a piece of the delicate membrane which
holds the intestines was laid under the
microscope, and kept moist by an assistant. The
observer's eye looked down upon a wild racing
of myriad blood-discs through the tiny vessels of
the transparent membrane. Presently the assistant
puts a drop of venom upon the tissue we
are studying. For thirty seconds there is no
change. Then suddenly a small vessel, giving
way, is hidden by a rush of blood-discs. A
little way off another vessel breaks, then a
third, and a fourth, until within five minutes the
field of view is obscured by blood, which at last
causes a rupture in the delicate membrane
between whose double folds the vessels run to
and from the intestine. We are now as near to
the centre of the maze as we are likely to come:
nearer than we have come with most poisons.
We have learned that this bland, tasteless
venom has the subtle power to forbid the blood
to clot, and in some strange way to pass through
the tissues, and to soften and destroy the little
blood-vessels, so that they break under the
continuing force of the heart-pump.

The same phenomena may be seen on the
surface of an open wound treated with venom;
and that which happens in the wound, and, in
the experiment just described, goes on at last
everywhere in the body, so that in dozens of
places vessels break down, while the blood is
powerless to check its own wasteful outflow, as
it would have done in health.

We have dwelt so long upon the symptoms
of the protracted cases of snake-bite as to have
lost sight for a time of the smaller class of
sufferers, who perish so suddenly as to forbid us
to explain their deaths by the facts which seem
so well to cover the chronic cases. These
speedily fatal results are uncommon in man, but
in small animals are very frequent.

It is common to see pigeons die within ten
minutes, and in these instances no trace of
alteration can be found in the blood or solid
tissues. Upon considering, therefore, the two
sets of cases, it seems pretty clear that the
venom has, besides its ability to alter the blood
and enfeeble the vessels, some direct power to
injure the great nerve-centres which preside
over locomotion, respiration, and the heart's
action.

To describe the experimental method by
which these conclusions were reached would
demand the space of another article, and
involve a full explanation of the modern means
of studying the effects of poisons; so that for
this reason we must beg the reader to accept
the proposition without being troubled with the
proof.

It were well if the record of horrors ended
with the death or the recovery; but in countries
where poisonous snakes are abundant and cases
of bite numerous, it is not uncommon to find
that persons who survive become the victims
of blindness, skin disorders, and various forms
of palsy.

Fortunately the average snake-bite, even in
India or Martinique, is far less fatal than was
once believed; so that even dogs, when bitten,
are by no means sure to die. Thus, of nine so
treated on one occasion, only three perished;
while among the eighty cases of venom poisoning
in man recorded in American medical journals
up to 1861 we have but four deaths. This
unlooked-for result is due chiefly to the fact, that
the danger is directly as the amount of venom,
and that the serpent, unless very large and long
at rest, or in captivity, can rarely command
enough to kill a man. Once aware of these
facts, it is easy to see why so many remedies got
credit as antidotes in a disease supposed to be
fatal, and in reality not at all so.