SNAKE POISON. 57 



venom. By appropriate experiments they excluded micro-organisms, 

 ferments, alkaloids, ptomaines, and crystalline acids. 1 They next showed 

 that there are three proteids in the secretion ; one, an albumin, is not 

 irulent ; but the other two, which are proteoses (proto- and hetero-pro- 

 teose), are extremely poisonous. Their action is the same as that of the 

 venom itself. They, like the venom, can be momentarily boiled without 

 impairing their activity, but prolonged boiling for days destroys their 

 virulence. 



The action of the poison is local and general. The most marked 

 local effect is oedema ; the general symptoms in non-lethal doses consist 

 of twitching and convulsions. A fatal dose kills within a few seconds 

 or minutes. There is also a peculiar effect on the blood. More than a 

 century ago, the Abbe Fontana 2 noticed that the blood of animals 

 killed by viper bite remained fluid. Brainard, 3 writing more than forty 

 years ago, states that when death occurs immediately, in animals bitten by 

 rattlesnakes, the blood is found at the post-mortem examination to be 

 clotted ; but if some time elapses before the animal succumbs, the blood 

 remains fluid in the vessels. The continued fluidity of the blood has 

 since then been noted by numerous observers in the case of various 

 snakes. These observations are explained by C. J. Martin's researches. 

 He found that different doses produce different results. Immediately after 

 the introduction of the venom, the coagulability of the blood increases, 

 and this increase in the case of moderate or large doses (more than 

 O'OOOl grm. per kilog. of body weight) culminates in intravascular 

 clotting of greater or less extent. The injection of smaller doses 

 produces a transient phase of increased coagulability, but after two 

 minutes this is succeeded by a negative phase ; the blood when drawn 

 either fails to clot at all, or does so only after the lapse of several hours. 

 The thrombosis occurs more readily in venous than arterial blood, and is 

 frequently confined to the portal area. These results show a great 

 resemblance between the action of the venom and that of nucleo-proteid. 

 The effect of diminished coagulability is not unexpected, seeing that the 

 principal substance in the venom is proteose, but the minuteness of the 

 dose necessary is very striking and distinctive. The smallness of the dose 

 suggests that the injected material does not itself contribute to fibrin- 

 formation. It probably acts by producing disintegration of the cells of 

 the endothelium of the blood vessels, or, according to Martin's later 

 observations, of the red corpuscles ; in either case the result would be 

 liberation of nucleo-proteid material. 



With regard to the question of how these poisonous proteoses are 

 formed, Martin puts forward the following hypothesis: the cells of 

 the venom gland exercise a hydrolysing agency on the albumins supplied 

 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 hydratioii stops 

 short at the proteose stage, and is not continued so as to form peptone, 

 or simpler nitrogenous materials, like leucine, tyrosine, or alkaloids. 

 Gland epithelium is certainly capable of exercising such a hydrolysing 

 influence; the conversion of glycogen into sugar in the liver cells is 

 one of the best known examples. 



1 A questionable trace of organic acid found did not possess toxic properties. 



2 Fontana, "Poisons," Trans, by J. Skinner, London, 1787. 



3 Rep. Smithson. Inst., Washington, 1854. 



