CHAPTER XVII. 
CYTOLYSINS IN SNAKE VENOM. 
The death-dealing neurotoxins and the hemorrhagins are most important 
of all cytolysins contained in snake venom, and the best-studied are the heemo- 
lysins, including the erythrocytolysins and leucocytolysins. Full descriptions 
of these three groups of cytolysins have already been given elsewhere under 
separate headings and I shall not repeat them in the present section. 
Apart from the neurolysins, hemorrhagins, and hemolysins several other 
cytolysins have been demonstrated in snake venom by Flexner and Noguchi,’ 
and somewhat later by Calmette and Noc.? 
The results of experiments obtained by Flexner and Noguchi are given in 
table 13. The venoms employed were those of Cobra, Ancistrodon piscivorus, 
Crotalus adamanteus, Daboia russellii, and Lachesis flavoviridis. 
The animal cells came from a wide range of animals, including warm- 
blooded and cold-blooded species. The former, limited to certain species 
of mammalia, had served for the study of the effects of venom upon the cells 
of the liver, kidney, and testes; the latter for that upon the spermatozoa, ova, 
and nerve cells. The cells were obtained by preparing emulsions of the solid 
organs and by suspending the expressed spermatozoa or separated ova in 
appropriate fluids. In the case of warm-blooded animals 0.85 per cent 
saline solution, and in the case of the marine animals fresh sea-water, were 
employed. The strength of the emulsions of the cells was approximately 
5 per cent of the organs used. 
The venom was dissolved in 0.85 per cent saline solution or in sea-water. 
The temperature to which mixtures of emulsion and venom were exposed 
were those of the room or thermostat (37° C.), depending, usually, on the 
origin of the cells. Observations of the effects were made (1) in test-tubes 
with the naked eye and (2) by means of microscopical examination. 
EFFECT OF VENOM ON CELLS OF WARM-BLOODED ANIMALS.’ 
The animals used in these experiments were dog, guinea-pig, rabbit, rat, 
and sheep. The venoms employed were daboia and crotalus. The experi- 
ments given would seem to prove conclusively that venom contains solvents 
for the parenchymatous cells of several animals, and that considerable dif- 
ferences in activity in this respect occur, according to the source of the venom. 
Flexner and Noguchi have also tested other venoms, for example, from the 
cobra, water-moccasin, and habu, and have found them to possess similar 
cytolytic properties; but their experiments show that daboia venom contains 
the most and crotalus venom the least active solvents, the other venoms 
arranging themselves in the order: water-moccasin, cobra. (Table 13.) 

1 Flexner and Noguchi. On the plurality of cytolysins in snake venom. 
2Noc. Sur polars propriétés physiologiques de différents venins de serpents. Ann. Inst. Pasteur, 
1904, » 387. : 
3 Rabbits’ s atozoa are seen to stop their motion under the influence of crotalus venom. (Weir 
Mitchell and Reichert.) 
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