340 EFFECTS OF SNAKE \EN()MS ON DOMESTIC ANr.MALS. 



or full, whether it has bitten recently or not, ^md whether it has 

 been for a long time in capitivaty or not. The largest amount can 

 possibly be obtained from the King Cobra, and the smallest from 

 some species of Hydropinse. 200 mgs. of dried venom, repre- 

 senting about 670 mgs. of venom, have been obtained from a 

 cobra {A^oja Ilajc) in an experiment lasting over a i)eriod of four 

 months. 



Chemical and Physical Proim-:rt[i:s of X'exom. 



The different venoms vary very much in ])hysical characters. 

 Cobra venom is a clear, yellowish Huid, slightly viscid, and may 

 sometimes be slightly opaque owing to the presence of epithelial 

 scales. It is i)ractically odourless, has a disagreeable taste, a 

 very high specific gravity, and is acid in reaction. \\'hen dried 

 rapidly in the desiccator, it solidities into a transparent layer 

 resembling gum arabic, this layer cracking in various directions 

 on further desiccation. 



The venom of Crutaliis varies from a pale emerald green to 

 orange or straw colour, and when dried resembles dried albumen. 

 It has neither taste nor smell. 



In this condition venom can l)e kept indelinitely, if protected 

 from light, air, and moisture. It is freely soluble in water, and 

 the resulting solution retains all the original properties of the 

 venom. \'enom owes its virulence to the |)resence of soluble pro- 

 teids, some of which — esj^ecially those which ])redominate in the 

 venom of the X'iperidre — are coagulated and parth' destroyed by 

 heat, and are completely destroyed by gastric juice. Others — 

 principally those which predominate in the venom of the Colu- 

 bridse — are unaffected by gastric digestion or heat under boiling- 

 point. All are. however, destroyed by pancreatic juice and pro- 

 longed boiling. Strong caustics, and strong oxidising agents 

 which destroy i)roteids, or preci])itate them from solution, render 

 venoms inert. Oi such agents hypochlorite of lime and perman- 

 ganate of potash are good examples. 



General Actions of Venoms. 



The general actions of venoms have been studied by numer- 

 ous observers. The ancients recognised snakes which they 

 described imder the names of Echis and Colitbra, and their 

 methods of treatment were based on attempts toi prevent absorp- 

 tion, namely, ligation, scarification, and subsequent cupping or 

 sucking of the wounds made. The effects of viper bites on ani- 

 mals were studied experimentally in the sixteenth century by Ridi 

 and Morse Charas, and the important fact that the venom pro- 

 duced coagulation of the blood in animals bitten was noted. 

 These workers came to the conclusion tliat the coagulation was 

 the cause of death. 



Weir Mitchell and Peicbert, in 1886, i)ublished a very com- 

 prehensive paper in which tliey stated that the active ])rinciples 

 of snake venoms were globulins and peptones. This was later 

 confirmed by Wolfenden^ and Karlbach. and the theory of the 



