THE VENOM 



indiarubber sheeting, or by chloroforming the snake and squeezing 

 the poison out of the glands into a vessel. 



In order to preserve this venom, it must be quickly dried over 

 calcium chloride or sulphuric acid in a desiccator, when it will keep 

 for years — e.g., Weir Mitchell kept his Crotahis venom for twenty- 

 three years, and then found it active. 



Physical Characters. — The quantity of the venom obtained 

 depends upon many factors, such as the general condition and size 

 of the snake, whether it has previously ejected venom, and whether 

 it has been long in captivity- — -a condition in wliich the secretion 

 diminishes. 



An adult cobra in good condition is said by Martin to give from 0'6 c.c. 

 to I'l c.c, and this should yield from 200 to 370 milligrammes of solids. 

 Calmette gives 124 milligrammes of liquid venom, yielding 35 milligrammes 

 of dry venom for Naja haje Linnaeus, 



The water-snake, Enhydrina valakadien Boie, gives only 9*4 to 2*3 milli- 

 grammes of dry venom, according to Rogers. 



A Vipera russellii Shaw gives from o*6 c.c. to I'O c.c. of liquid, which yields 

 150 to 250 milligrammes of solids. 



According to C. J. Martin, Notechis scutatus Ptrs. gives 205 milligrammes of 

 liquid, containing 73 milligrammes of solids, Notechis pseudectis 160 milli- 

 grammes of liquid and 94 milligrammes of solids. 



According to Calmette, Laches is lanceolatus Lacep. gives 320 milligrammes 

 of liquid venom, containing 127 milligrammes of solids. Cerastes cornuttts 

 Forsk. from Egypt gave 123 milligrammes of liquid and 27 milligrammes of 

 solids, and Crotalus confluentus Say gave 370 milligrammes of liquid and 

 105 milligrammes of solids; while Crotalus durissus L., according to Flexner 

 and Noguchi, yields from 309 to 179 milligrammes of dry venom; and 

 Ancistrodon piscivorus Lacep. from 180 to 125 milligrammes. 



The different venoms vary in physical characters, as may be 

 judged by a few descriptions. 



Cobra-venom, when fresh, is a transparent, almost colourless 

 fluid, with a syrupy consistence and a disagreeable bitter taste. 

 When dried, it becomes yellowish-brown, and may be kept for 

 months. It can decompose and become of a dark brov/n colour, 

 possessing a disagreeable odour. 



Crotalus-venom, according to Mitchell, may vary from a pale 

 emerald-green to an orange or straw colour, and when dried re- 

 sembles dried albumin. It has no taste or smell. 



The poison varies, being clear and limpid or pale straw or yellow 

 in colour, which is said to vary with the degree of pigmentation 

 of the snake and the concentration of the venom. The specific 

 gravity varies from 1030 to 1044 (Weir Mitchell) for Crotalus, 

 iiio for Cobra, and 1077 for Vipera russellii. Microscopically, 

 there may be only a few epithelial cells and salivary corpuscles 

 and bacteria, all due to contamination with fluids from the mouth. 



Chemical Analysis.- — ^The reaction of pure venom, is acid. 



The ultimate analysis was made by Armstrong for Sir Joseph 

 Fayrer, and is as follows : — 



Crude Dried Poison. 

 Carbon . . . . . . . . . . . . 43"55 



Nitrogen 13-43 



