68 INTRODUCTION 



such proteids have hitherto been unsuccessful. 

 Accordingly, at the present time we must regard 

 such toxic principles as residing in some special 

 grouping of a portion of the atoms in the complex 

 venom proteid molecule. The analysis of their 

 physiological actions has proved them to be made 

 up of a great many more constituents than would be 

 imagined from their chemical composition. 



The effect of the poison of Proteroglyphous , 

 Colubrids (Hydrophids, Cobras, Bungarus, Elaps, 

 Pseudechis, Notechis, Acanthophis) is mainly on the 

 nervous system, respiratory paralysis being quickly 

 produced by bringing the poison into contact with 

 the central nervous mechanism which controls 

 respiration ; the pain and local swelling which 

 follow a bite are not usually severe. 



Viper poison {Viper a, Echis, Lackesis, Crotalus) 

 acts more on the vascular system, bringing about 

 coagulation of the blood and clotting of the 

 pulmonary arteries ; its action on the nervous 

 system is not great, no individual group of nerve-cells 

 appears to be picked out, and the effect upon respira- 

 tion is not so direct ; the influence upon the circulation 

 explains the great depression which is a symptom 

 of Viperine poisoning. The pain of the wound is 

 severe, and is speedily followed by swelling and dis- 

 coloration. The symptoms produced by the bite of 

 the European Vipers are thus described by the best 

 authorities on snake poison (Martin and Lamb) : 



