140 VENOMOUS SNAKES AND THE PHENOMENA OF THEIR VENOMS 
guinea-pig’s blood, the blood becomes black and forms no coagulation, while 
0.005 gm. produced a black clot after one hour, and no serum separated 
when examined the next day. The quantities of 0.0025 gm. and 0.00125 
gm. in 1 c.c. of saline solution and mixed with 1 c.c. of guinea-pig blood 
retarded coagulation only a few minutes or about 10 minutes, and ren- 
dered the color of the clot very black, no serum exuding from it the next 
day. It is interesting to see that throughout the entire experiment, while 
saline-isotonic solution without venom required 6 minutes for coagulation, 
the mixtures containing 0.000625 gm.,0.000312 gm.,and 0.00007 gm. produced 
coagulation in 2 minutes and a red-stained serum separated out. ‘The clots 
in these tubes became semi-fluid the next day. The quantities of 0.000028 
gm. and 0.000004 gm. allowed the blood to form a bright red clot, from which 
stained serum was separated out when examined the next day. 0.000002 gm. 
in 1 c.c. mixed with 1 c.c. of the blood did not exert any influence in regard 
to coagulation and subsequent serum exudation, which was exactly the same 
as with the control. 
Using the doses of from 0.0002 to o.oo01 gm. of cobra venom per I c.c. of 
the blood, they have demonstrated the specific anti-inhibitory property of 
Calmette’s antivenin upon this venom. ‘Their conclusions are: 
(1) Cobra venom delays or inhibits the clotting of the blood in vitro. 
(2) This inhibitory action is neutralized by antivenomous serum im vitro. 
(3) This action of antivenomous serum in vitro is specific. 
(4) Antivenomous serum itself, when added to blood, delays clotting. 
(5) For a certain dose (o.coor gm.), the measure of the neutralization in 
vitro, using clotting as a test reaction, is also the measure of the neutralization 
in corpore for guinea-pigs. 
(6) The neutralization of the toxin by its antitoxin, in vitro, is certainly not 
vital nor cellular, but must be chemical. 
Lamb and Hunter were able to show that the injection of a large amount 
of cobra venom into a vein of rabbit never produces intravascular throm- 
bosis, but causes some deficiency of coagulability of the blood. ‘The diminu- 
tion of coagulability was found to be more pronounced the larger the amount 
of venom injected. This fact seems to furnish an easy explanation why 
Wall, who used a small quantity of the venom, failed to obtain diminished 
coagulability, while Cunningham,’ who killed the animal in a few minutes 
with a much larger amount of cobra venom, observed the loss of the clotting 
power of the blood of the animal after its death. 
Here a most striking difference in the physiological action of the cobra and 
daboia venoms is brought to light. The former produces, if employed strong 
enough, a state of diminished coagulability without producing any increased 
clotting power, while the latter produces, if in larger quantities, a sudden 
increase of coagulability, culminating in an instantaneous thrombosis in the 
1Kanthack and Cunningham both observed that the blood running into a strong solution of cobra venom 
either remained permanently unclotted, or the clot which formed after considerable delay was 
soft and gelatinous and no serum exuded. 
