ICJ-FKCTS OF SNAKl; \KNOM;-. ON DOM!".STK' ANIMALS. 343 



haemolysis could be produced in the presence of venom by the 

 addition of complement, in the horse, man, dot:", rabbit, and 

 guinea-pi.i^f the venom alone could haemolyse the washed cor- 

 l)uscles. and they cairie to the conclusion that there was an endo- 

 complentent present in the red cell itself, attached to the stroma. 



Thev conchided. fiu-ther. that it is the lecithin of the stroma 

 which acts as a complement. Kyes found that the lecithin was 

 acti\e with the blood cells of all the species which he examined, 

 and that the qtiantit} necessary for haemolysis was the same for 

 the blood cells for the various s])ecies of animal. 



At present it is therefore considered that snake venom pro- 

 duces hccmolysis 1j_\- its ambocejjtors uniting with the comple- 

 ments contained in the sera of the majority of animals, and that 

 these com])lements beloncr to the class of fatty acids and soai)s. 

 and. further, that in certain species there are endo-complements 

 in the erythrocytes attached to the stroma of the corpuscles of 

 the same nattire as those in normal sera. 



Hconorrhagin. — Investij^ations into the action of Crotalus 

 venom showed that when this venom was applied to the mesen- 

 tery, blood escaped from the vessels owing- to damage to their 

 walls. Flexner and Nogtichi. working in this connection, fotind 

 that this ])roperty was lost if the venom was heated to 75 degrees 

 Centigrade for 30 minutes, and they named the toxic jirinciple 

 liKmorrhagin. 



Its action was studied \)\ intra-peritoneal injecti(jn of venom 

 and subsequent examination. It was found that the extravasa- 

 tion of blood |irodticed was not dtte to diapedesis, but to actual 

 rtipture of the walls. ai)parently due to a cytolytic action of the 

 venom on the endothelial cells of the capillaries and smaller 

 veins. 



I'ihriii Ferine II I. — A hbrir. ferment was shown to be i)rescnt 

 in the venoms of the X'iperiche. and also in some of the Colu- 

 bridae by Martin. In the former it is the active princi])le which 

 causes intravascular clotting in small animals, associated with 

 sudden onset of convulsions and death. 



Natl'RK and Action of N'fnoms. 



From a biological point of view, venom may be regarded as 

 essentially part of the digestive mechanism, and to an animal 

 which swallows its prey with the integument intact, it is of con- 

 siderable advantage to be able to impregnate it with ])owerful 

 solvents and ferments. It is generally agreed that in the venom of 

 the ColubridEe. neurotoxins, with a specific affinity for the respira- 

 tory centre, prepondei'ate. and that in the Viperid?e toxins, which 

 act on the blood and circtilatory system, preponderate ; while 

 among Australian Colubrines venoms are found which are rich 

 in both classes of toxins. In the Hydropinse the venom is 

 almost purely neurotoxic in effect. 



It must be understood, liowever. that in any given venom, 

 especially those which act chiefly on the blood system, one toxic 



