38 SNAKE-POISON AND ITS ACTION. 



If we turn from these to the black snake (Pseude- 

 chis 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 collapse, and 

 from the combined effects of this and heart failure 

 death takes place suddenly and quickly as if in a faint- 

 ing 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 gener- 

 ally much extravasation of blood locally. Muscular 

 paralysis is also less pronounced, but sudden collfipse 

 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 haemorrhage, does not occur with either. 



