114 



PROTEIDS. 



injected into them ; and various proteids produced by bacteria, the 

 so-called toxalbumoses. 



The two classes of these poisonous proteids which demand more 

 than a passing notice are snake-poison and the bacterial poisons. 



Snake-poison. The first snake-poison isolated was viperin 

 from an adder. Subsequently crotalin was obtained from the 

 venom of a rattlesnake, and its albuminous nature was recognized ; 

 and later the venom of the cobra and other poisonous snakes was 

 studied. It has been demonstrated that in the venom of the Aus- 

 tralian black snake there are three proteids : One, a non-virulent 

 albumin, and the two others, which are virulent, are proto- and 

 heteroproteose. The poison produces intravascular coagulation of 

 the blood, probably by causing a disintegration of the cells of the 

 endothelium of the vessels or of the red corpuscles, thereby pro- 

 ducing or setting free a nucleoproteid. In discussing this sub- 

 ject, Halliburton, in Schafer's Physiology, to which we are indebted 

 for this resume of proteids or poisons, says that with regard to the 

 question how these poisonous proteoses are formed, C. J. Martin 

 puts forward the following hypothesis : The cells of the venom- 

 gland exercise a hydrolyzing (p. 119) agency on the albumin sup- 

 plied them by the blood, the results of which influence are the 

 poisonous proteoses found in the venom. A difference between 

 the process and digestion by pepsin, or by anthrax bacilli, is that 

 the hyd ration stops short at the proteose stage, and is not con- 

 tinued so as to form peptone, or simple nitrogenous materials, like 

 leucin, ty rosin, or alkaloids. Gland epithelium is certainly capable 

 of exercising such a hydrolyzing influence ; the conversion of 

 glycogen into sugar in the liver-cells is one of the best known 

 examples. The following table is given illustrating the analogy 

 between various hydrolyzing processes, proteid being in all cases 

 the material acted on : 



It has been ascertained that 0.00025 gram of the venom of 

 Hoplocephalus custus, an Australian snake, will kill a rabbit weigh- 

 ing a kilogram ; this is about the same virulence as the toxin of 

 diphtheria. 



Bacterial Poisons. Halliburton says that the word pto- 

 main was originally employed to designate those putrefaction-prod- 



