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 anæmic in appearance through increasing engorgement of the abdominal veins. Anæmia of the nerve-centres hastens the collapse, and from the combined effects of this and heart failure death takes place suddenly and quickly as if in a fainting fit. Here then we have an approach to the effects of viper poison which is also shown in the greater amount of swelling and effusion around the bite and in the bitten limb. This approach is still closer in the poison of the death adder (_Acantophis antarctica_). There is generally much extravasation of blood locally. Muscular paralysis is also less pronounced, but sudden collapse from vaso-motor paralysis not unfrequently takes place, when the patients fully conscious are still able to sit up. That leading feature of viper poison, diapedesis with hæmorrhage, does not occur with either. If we turn from Australian to Indian snakes, the peculiar tendency of the poison to concentrate its action on special nerve-centres becomes still more marked. The predilection of the cobra poison for the respiratory centre has already been dwelt on. More remarkable and strange is the action of the Indian viper-poison on the minute ganglia in the vaso-motor nerve ends, which control the capillary circulation, and by their paralysis bring about extensive hæmorrhage through diapedesis.