loyo VENOMS AND ANTIVENINS 



known to have a low protein content, are practically all dialyzable. However, all the 

 above-mentioned variations are due to the differences existing in the composition of 

 venoms. Each venom is a mixture of special chemical substances, showing peculiar 

 physico-chemical affinities and having different antigenic properties. 



c) Composition. — Very little is known concerning the chemical composition and 

 the real nature of the toxic principles of the venom. Faust^ is the only author who 

 claims to have isolated from the venom of Naja naja a non-albuminous substance 

 called "ophiotoxin" which he considered its active principle; and from the venom of 

 Crotalus adamanteus another substance which he called "crotalo toxin." His studies, 

 however, must be repeated by other biochemists before receiving general acceptance. 

 It is still to be proved whether both ophiotoxin and crotalotoxin have antigenic 

 properties and behave like the "antitoxinogens" recently referred to by Zinsser.^ In- 

 deed, the main feature of animal substances, such as bufotalin (toad venom), arach- 

 nolysin (spider venom), vegetable substances such as abrin, ricin, and crotin, the 

 bacterial leukocidins and hemotoxins, bacterial substances such as diphtheria and 

 tetanus toxin and the toxin of a few other micro-organisms, is their property of 

 eliciting the production of antitoxins in the animal body. Nevertheless, there is some 

 difference between snake venoms and bacterial exotoxins. As a rule, the former do not 

 show any incubation period, that is to say, there usually is no delay in the occurrence 

 of symptoms after their administration as is the case with the latter (exotoxins). But 

 each venom proves to have properties of its own, that of C terrificus, for instance, 

 acting slowly upon the organism, producing perceptible symptoms only after an 

 incubation of a few hours, and never causing even local pain. 



In general, crude venom consists of: (a) proteins (albumin, globulin); (b) pro- 

 teoses and peptones; (c) mucin and mucin-like substances; {d) ferments; (e) fat; (/) 

 detritus (cells, etc.) and micro-organisms — which, as a rule, are not found in properly 

 purified venoms; (g) salts (calcium chloride and calcium, magnesium, and ammonium 

 phosphate) . 



d) Antigenic principles. — The following principles have thus far been recognized 

 in the various snake venoms: 



Proteolysin and histocytolysins are phlogogenous and so cause local symptoms such 

 as pain, swelling, tissue destruction, and necrosis, while all the other principles exert 

 a general or systemic action on the organism. Proteolysin has a very marked potency, 

 either in vitro or in vivo, and is found especially in the venom of the solenoglyphous 

 families (Viperidae and Crotalidae). 



Cardiotoxin is responsible for the low blood pressure and heart failure which 

 follow the bite of a few species, namely, Naja naja, Micrurus corallimis, M. frontalis, 

 Daboia russellii, Agkistrodon mokasen and Crotalus atrox. 



Hemocytolysins are divided into erythro- and leukocytolysins, first, because some 

 venoms are capable of dissolving white cells after absorption by red cells and vice 

 versa; second, because some venoms, e.g., that of M. corallimis, have erythrocytolysin 

 but no leukocytolysin. 



Hemorrhagin acts on the endothelial cells of the capillaries, thereby causing 



' Faust, E.: Arch.f. exp. Path. it. Phannakol., 56, 236. 1907; 64, 244. 1911. 



* Zinsser, H.: Infection and Resistance, p. 41. 1923. 



