SNAKE-POISON AND ITS ACTION. 27 



through the porous cement substance by what little 

 " vis a tergo " there may be left yet, whilst in the 

 venous side, in the small veins corresponding with the 

 closed capillaries, engorgement must necessarily take 

 place through this "vis a tergo " being entirely absent, 

 and diapedesis, which here also has been observed, 

 follow in due course The writer has always been in- 

 clined to take this view, the correctness of which 

 appears to be borne out by an experiment recorded by 

 Feoktistow. He found on sprinkling a two per cent, 

 solution of snake-poison over the mesentery of an 

 healthy animal, that wherever a drop of the solution 

 fell, almost immediately the capillaries and small veins 

 became dilated and small point-like effusions of blood 

 appeared, gradually enlarging and ultimately becoming 

 confluent with adjoining ones. Large haemorrhagic 

 surfaces were thus formed in a comparatively short 

 time. Here paralysis of the nerve-cells interspersed 

 in the yaso-motor nerve-ends was evidently the first 

 effect, followed by dilatation of the capillaries and 

 immediately afterwards by effusion. Without some 

 obstruction within the capillaries, like that above 

 described, effusion in this purely local poisoning process 

 appears unexplainable. 



The special preference which the viper-poison has 

 for the vaso-motor sphere will hereafter be referred to. 

 Haemorrhages from Australian snake-poison are com- 

 paratively rare. Even at the bitten place there is as 

 a rule very little swelling and effusion and frequently 

 none at all. When it occurs it quickly disappears after 



