190:>.] and Antidotes of Colulrine and Viperine Venom*. 423 



Further, artificial respiration fails to improve the circulation after 

 respiratory failure, while, in the primary respiratory failure of 

 Colubrine poisoning, it is most effective. 



II. Trimenmrm anamallensis, the Indian representative of the Kattle- 

 snake class has also been examined (thanks to the kindness of 

 Dr. W. Dowson), with precisely similar general results to the others, 

 the same vaso-motor paralysis being induced by a small single intra- 

 venous dose without any intravascular clotting, as in the case of the 

 liattlesnake, while, in larger doses, it kills with intra-vascular clotting 

 like the true vipers. It has much less effect in causing haemorrhages 

 than either the Rattlesnake or the Puff-adder, but less than the 

 Daboia. 



Thus we find from a comparison of the action of these four Vipers 

 that while in the case of the two Pit- vipers a primary circulatory 

 failure, quite independent of any intra-vascular clotting, can be readily 

 induced by a single mtra-venous dose of the venoms, the same result 

 can also be brought about in the case of the two true Vipers by first 

 producing the negative phase of reduced coagulability by preliminary 

 small doses of the venoms. Further, there are cases on record of 

 complete loss of clotting power for several days, in which ultimate 

 recovery took place, while the hsemolytic changes, which are produced 

 by all these venoms, are not of lethal intensity. The failure of respira- 

 tion is always secondary to that of the circulation, while none of 

 these venoms have any marked direct paralysing action on the heart 

 which could account for the circulatory failure. 



On the other hand, we find a complete paralysis of the vaso-motor 

 centre in the medulla is common to all these venoms, and will fully 

 account for the lethal effects found, although in some of them- the 

 hjemorrhagic effects will greatly aid it. If my conclusion is correct 

 that the essential action of the Viperine poisons as a class is a paralysis 

 of the central vaso-motor centre, just as the Colubrine class paralyse 

 the respiratory centre, then it would appear to be possible to produce 

 an aritivenin against the former venom on the same lines as Calmette's 

 serum against the Colubrine class, a mixture of Viperine poisons being 

 used for injections. In the meantime such drugs as adrenal extract 

 and nicotine, together with cardiac tonics, may be of material value in 

 doubtful borderland cases, in keeping up sufficient blood pressure to 

 insure a sufficient supply of blood to the medulla to maintain the 

 respiratory centre working. 



