THE VENOM 



■255 



containing some, but not in any one venom all, of the following 

 active principles : — • 



1. Neurotoxins. 



(1) Acting principally on the respiratory centre. 



(2) Acting principally on the vasomotor centre. 



(3) Acting upon nerve end-plates in striated muscle, par- 

 ticularly on those of the phrenics. 



2. Agglutinins. 



3. Cytolysins. 

 [a) Haemolysins. 

 (6) Leucolysins. 



(c) Hsemorrhagins. 



[d) Other cytolysins. 



4. AntihcBmolysins. 



5. Antibactericidal substances. 



6. A fibrin ferment, 

 y. An anti fibrin ferment. 

 ^.^A proteolytic ferment. 

 9. A cardiac and vascular tonic. 



Of these principles, the most important are the neurotoxins, the 

 cytolysins, and the fibrin ferment. 



The analysis of the venom, according to Martin, may be effected by : 



(1) Dialyzing and filtering the venom through a gelatin filter 

 supported in the pores of a Pasteur-Chamberland filter. Fibrin 

 ferments and hcemorrhagins do not dialyze. 



(2) Heating from 70° to 100° C, when some neurotoxins and 

 some hcemolysins will not be affected. 



{3) Haemolysins can be separated from neurotoxins by digestion 

 with red blood cells mixed with serum which has previously been 

 : heated to 56° C. 



Neurotoxins and other cytolysins can be separated by the method 

 of Flexner and Noguchi, which will be described later. It must be 

 clearly understood that the venom of any one snake does not 

 contain all these principles. 



I. Neurotoxins. — ^The neurotoxins are the most important 

 active principles of the venom of many snakes, especially the 

 colubrine snakes. They have been studied in Ancistrodon con- 

 tortrix by Flexner and Noguchi, who tested the anchoring power 

 of the various tissues of the body for the principles in venom in 

 the following manner: — They took a definite weight of tissue 

 washed in tepid, sterile, normal saline solution, and after triturat- 

 ing it in a sterile mortar, mixed it in test-tubes with a given number 

 of minimal lethal doses (M.L.D.) of the venom. The mixture, after 

 being placed in a thermostat for one hour, was centrifugalized, 

 and the supernatant fluid injected into guinea-pigs. They firsi 

 took 2 grammes of the organs, and mixed them with three times 

 M.L.D. , calculating that after centrifugalizing there should be le/^ 

 at least two M.L.D. 



