little more in
detail. Apart from quantitative differences in the poison imparted, they
arise principally from the strange capriciousness with which the poison
concentrates its action on special nerve centres and leaves others
comparatively intact.

The nearest approach to regularity and orderly sequence of the symptoms,
as described in the foregoing pages, we find in Australia after the bite
of the tiger snake (_Hoplocephalus curtus_) and the brown snake
(_Diemenia superciliosa_), more especially that of Queensland. Here we
can trace the action of the poison distinctly from centre to centre,
from the lowest part of the anterior cornua up to the cortex cerebri,
and even throughout the sympathetic ganglia as far as they are patent to
observation. The poison of these snakes is extremely diffusible and
quickly absorbed. It spreads with rapidity and nearly equal force over
all the motor centres, the symptoms following each other so quickly as
almost to appear simultaneous, though, in reality, successive. But even
the poison of these snakes leaves the arms only slightly paretic, when
paralysis in all the other voluntary muscles is well pronounced, and
does not paralyse them until coma has set in. It also touches the
respiratory centre but slightly. Sometimes coma is light and the
patients can be roused for a little while, at other times it is deep and
lasts till death. But even greater variations are observed occasionally.
In one very extraordinary case of tiger snakebite, the patient, a child
of 9 years, remained conscious to the last, and after vomiting blood
freely died under symptoms of heart failure. In rare cases the symptoms
resemble those of cobra poison.

If we turn from these to the black snake (_Pseudechis porphyriacus_) a
different picture presents itself. Its poison does not produce so deep a
coma and often none at all. The patients generally feel drowsy and fall
asleep, but are easily roused and sometimes awake spontaneously. There
is also not the same amount of muscular paralysis. They are frequently
able to walk a few steps with assistance and can move in bed, the arms
especially being almost free from paresis. But the insidious poison none
the less does its work, though its effects are less patent. It
concentrates its action on the vaso-motor centre. The victims from hour
to hour become more anaemic in appearance through increasing engorgement
of the abdominal veins. Anaemia of the nerve-centres hastens the