CHAPTER VI. 
TOXIC SECRETIONS OF VENOMOUS SNAKES. 
AMOUNTS OF VENOM SECRETED. 
The quantity of venom yielded at one time by a snake, either at a single 
bite or by squeezing the poison glands, is very variable. It increases, how- 
ever, in general, in proportion to the size of the snake, although this rule 
can not be applied to the marine snakes, which secrete an amount that is 
small in comparison to their size. The continuous failing of health in cap- 
tivity causes a decrease of venom, both in quantity and in toxicity; especially 
is this the case where the snakes refuse to take nourishment and are sub- 
jected to repeated extractions of venom. While it is very important to deter- 
mine the exact amounts of venom yielded at a single bite, the data bearing 
upon this subject are rather unsatisfactory. 
Weir Mitchell has noted the difficulty of extracting venom from the rattle- 
snakes when the latter are resisting forcible manipulation. He has found 
that more venom can be extracted when the snakes are put under the effect 
of an anesthetic, thus relaxing the muscular resistance. Lamb’s careful 
study of the Indian cobra showed that the amount of venom thrown out vol- 
untarily by a snake is larger than that obtained through forcible compression. 
Calmette gives the detailed results of his experiments on two specimens of 
Naja haje, about 5.5 feet long. During 120 days in his laboratory one was 
subjected to 5 and the other to 6 extractions. In the fresh state the total 
amount of the venom for the first specimen was 0.581 gm. (per 5 extractions) 
which weighed 0.174 gm. in the dried form. The second snake afforded 
(on 6 extractions) 0.684 gm. fresh venom, which weighed 0.202 gm. on dry- 
ing. Thus the average single amount of venom to be ejaculated by the adult 
0.581 + 0.684 0.174 + 0:202 
5 + 6 oe 
= 0.0331 gm. in the dried form. He also found that 1 gm. of the fresh venom 
weighed 0.336 gm. upon complete desiccation over calcium chloride. With 
Naja tripudians, Cunningham estimated the amount of a single bite at 0.254 
gm. (dried); Lamb at 0.231 gm. (extracted with fingers, dried) ; 0.373 gm. (by 
voluntary bite, dried); and Rogers at 0.249 gm. (dried). 
With Pseudechis porphyriacus, MacGarvie Smith gives the amounts of 
single bite at 0.1 gm. to 0.16 gm. in the fresh state and 0.024 gm. to 0.046 gm. 
in the dried form. 
With Notechis scutatus s. Hoplocephalus curtus the same author gives the 
amount of venom produced at a single bite at 0.065 gm. to 0.15 gm. liquid 
and 0.017 gm. to 0.055 gm. dried. The dried venom weighed from 9g to 38 
per cent of the fresh venom. 
Daboia russellii yields on an average 0.15 to 0.25 gm. weighed dry (Lamb). 
70 
Naja haje is = 0.115 gm. in the fresh state and 
