POISON OF SOME INDIAN VENOMOUS SNAKES. 37 



merits with perfectly fresli poison and the dried residue of 

 a similar quantity ; but there are few, if any, instances on 

 record of death from the fresh poison in less than half a minute, 

 the time in which the dried poison killed a guinea-pig in 

 Experiment XXVIII. 



The local action of the poisDu, however, seems to be altered 

 by drying ; for extravasation of blood around the part where 

 a snake has inserted its fangs, or venom has been injected, is 

 one of the most prominent effects produced by the fresh poison, 

 whereas it is very slight, or absent altogether, when the dried 

 venom has been employed, except in occasional instances, such 

 as Experiment LVII. 



Dilution seems also to have no effect in lessening the activity 

 of the venom, except so far as it retards absorption ; for it is 

 evident that a drop of pure poison, injected subcutaneously, is 

 likely to find its way into the circulation more quickly than the 

 same quantity diluted with a hundred times its bulk of water. 



Coagulation of the venom by alcohol does not destroy its 

 activity, as we have shown in our former communication. The 

 coagulum thrown down by the alcohol is innocuous, or nearly 

 so ; but the poisonous principle remains in solution, and the 

 alcoholic extract possesses similar properties to the poison 

 itself. A specimen of poison was received from India in a 

 coagulated state ; but we are uncertain whether this occurred 

 spontaneously or was produced by the action of reagents. It is 

 probable, however, that it was due to its having been mixed, in 

 order to preserve it, with alcohol, which had evaporated before 

 we received it. It was active, as Experiment XI shows. 

 Coagulation by boiling does not destroy the activity of the 

 poison (Experiment XII) ; but a portion which was boiled for 

 more than half an hour under pressure corresponding to a 

 temperature of 102° C, had no effect when injected under the 

 thigh of a lark. The notes of this experiment have unfor- 

 tunately been lost. Admixture with liquor ammonias and liquor 

 potassse does not alter the effects of the poison. This appears 

 from Experiment XIII, and from several made by Dr. Fayrer 

 in India. 



