TOXIC SECRETIONS OF VENOMOUS SNAKES 71 
With Lachesis lanceolatus (fer de lance) Calmette gives 0.320 gm. in the 
fresh and 0.127 gm. in the dried form for a single extraction from both glands. 
With Crotalus adamanteus,' Flexner and Noguchi put the figures at between 
0.179 gm. and 0.309 gm. in the dried form for a single extractable amount 
from both glands. 
With Crotalus confluentus, Calmette gives 0.370 gm. in liquid and 0.105 gm. 
in dried form from a single bite. 
With Ancistrodon piscivorus, Flexner and Noguchi estimated 0.125 gm. to 
0.18 gm. dried as a single extractable dose. 
With Ancistrodon contortrix the same authors found the average to be 
0.03 gm. to 0.06 gm. dried. 
With two large Egyptian Cerastes specimens Calmette derived 0.125 gm. 
(0.027 gm. in dry) and 0.085 gm. (0.019 gm. in dry), respectively. 
With Enhydrina, Rogers could extract only 0.0023 gm. to 0.0094 gm. (as 
dried form) from both glands of the adult specimens. 
The loss in weight of venom upon drying has been estimated by various 
authors. Weir Mitchell and Reichert found it to lie between 25.15 per 
cent to 27.42 per cent with Crotalus adamanteus, C. atrox, and Ancistrodon 
piscivorus. Calmette places it at 62 to 80 per cent. C. J. Martin found 
the loss in weight after drying the Australian venom to be 33 per cent, while 
Flexner and Noguchi found the solid portion of venom (Crotalus and An- 
cistrodon) to range from so to 7o per cent of the total weight. 
TOXICITY OF SNAKE VENOM. 
Irrespective of the modes of action by which the fatal issue of the venom 
poisoning is brought about, it is possible to determine the approximate mini- 
mal lethal dose of each snake venom for a given species of animals by intro- 
ducing the venom directly into the system of that animal. It may be stated 
that certain venoms act more powerfully when introduced directly into the 
blood circulation, while others do not appreciably differ in their final out- 
come, whether they are given subcutaneously or intravenously. Thus, a 
much smaller quantity of the venom of Crotalus is effective when injected 
intravenously than when injected intraperitoneally or subcutaneously, while 
but little difference is shown with the venom of Cobra in these respects. It 
is superfluous to emphasize the fact that venoms from different species of 
snakes differ slightly or widely in their constitution, which is always multiple 
in nature, and also in their physiological effects. A powerful venom means 
one which kills or injures the victim by a smaller amount than a weak venom. 
The cause of these qualitative differences will be treated later im extenso. 
The susceptibility of animals to venom is also very variable. Speaking 
in general, warm-blooded animals are more sensitive to the action of venom 
than cold-blooded animals. There exists among various species of animals 
a constant susceptibility peculiar to each group. 
In regard to the toxicity of venom we find certain constancy of strength in 

1 Weir Mitchell (1861) states the following details: Crotalus durissus, No. 1, 18 in., 9} 0z.; venom ri 
drops. No. 2, 25 in., 18 oz.; 19 drops. No. 3, 49} in., 34 lbs.; 29 drops. 
