44: ON THE NATURE AND ACTION OF THE 



Action of Cohra-poison upon the Blood. 



The blood of animals killed by cobra-poison generally 

 presents a dark colour, as death is due to failure of the 

 respiration and not of the circulation ; but it readily assumes a 

 florid colour when exposed to air. The same is the case with 

 the blood of animals poisoned by Dahuia-yenom (Experiments II, 

 V, and Vl). 



Coagulation usually occurs readily and firmly in the blood of 

 animals killed by cobra-poison, while it is frequently absent 

 from the blood of those killed by that of the Daboia. In 

 experiments made in India, this occurred almost invariably : 

 and it is illustrated by Experiments II and IV. In Experi- 

 ments I, V, and VI, however, coagulation occurred in the blood 

 of a pigeon and guinea-pig poisoned by Daboia-Y Qnom. ; and a 

 similar occurrence has been sometimes observed by one of us 

 (Dr. Fayrer) in fowls bitten by this snake in India.* 



In numerous instances we have been unable to detect any 

 alteration in the blood-corpuscles after death from cobra-2:)oison ; 

 but in Experiments XXI and XXII we observed a most 

 distinct crenation in the corpuscles of rats poisoned by it. This 

 was probably due in some degree to evaporation, as in 

 Experiment XXI it was to a great extent prevented by 

 surrounding the preparation with oil ; but it indicates a change 

 in the blood, as the corpuscles did not present this appearance 

 before the injection of the poison — although they were prepared 

 for observation in exactly the same way, and were as much 

 exposed to evaporation in the one case as in the other. 



Experiment XXI. 



A drop of blood from the tail of a white rat was examined 

 microscopically. The corpuscles did not form rouleaux ; but no 

 trace of crenation could be observed in them. 



12.10. P.M. 0"018 gramme of dried cobra-poison, dissolved in 

 1 c.c. of water, was injected into the flank. Almost immediately 

 the nose of the animal began to twitch up every few seconds. 



* Thanatophidia of India, pp. 80, 100, 101, 10 k Tide Mr. Cunningham's 

 remarks. 



