^NAKE VENOMS, tBBIR PHYSIOLOGICAL ACtlON. 22^ 



the arteries are found full of solid clot. The heart has, of course, ceased 

 to beat. If the dose has been a smaller one, the clotting may be con- 

 fined to the pulmonary arteries, the right heart and the portal veins. 

 The degree and extent of the clotting depend on the amount of venom 

 injected and the rapidity with which it has been injected. But, in all 

 cases of rapid death resulting from Daboia intoxication, there can be 

 no shadow of doubt but that the fatal result has been caused by this 

 most extraordinary and remarkable intravascular clotting. The 

 symptoms which Cunningham interpreted as resulting from a direct 

 action of the poison on the central nervous system are due to carbonic 

 aoid poisoning, the result of the non-aeration of the blood in the 

 lungs. 



In the second group of cases, viz., that in which death is delayed for 

 sometime, we have several different phenomena presenting themselves. 



In the first place, death may follow in a few hours after the 

 injection. In such a case the fatal result is, I am sure, due to the 

 depressing action which the poison has on the heart. Thus I have 

 seen a horse, which had received into a vein a quantity not sufficient 

 to cause clotting, fall down quite collapsed ; its pulse has become 

 feeble, hardly to be felt ; its body cold and covered with perspi- 

 ration — a typical picture of cardiac depression or syncope, known 

 popularly as a faint. There was no paralysis : after a rest the 

 animal got up and walked about, only, however, to fall down again 

 in another faint. This condition sometimes ends in death, while, on 

 the other hand, it may be recovered from. 



In the second place, should the fainting condition be recovered 

 from, then a whole series of phenomena develops, which is dependent 

 on the action of the venom on the blood corpuscles, the coagulability 

 of the blood and the capillary walls. 



I have told you that when large doses are given either intra- 

 venously or subcutaneously, the coagulability of the blood may 

 become so increased as to lead to rapid intravascular clotting and 

 death. Should, however, the quantity be not sufficient to cause this 

 clotting, and especially will this be the case if the subcutaneous method 

 of injection has been used, then the very opposite condition of blood 

 coagulability results. In some cases the blood remains absolutely 

 unclotted when drawn into a test-tube, while in others it clots only 

 after a long interval of time, and the clot is very loose and soft. As 



