166 VENOMOUS SNAKES AND THE PHENOMENA OF THEIR VENOMS 
These two investigators made the experiments: (1) With a fixed volume of 
blood mixed with a fixed volume of cobra poison of known strength in a 
hemocytometer pipette, and the corpuscles in a given field counted from time 
to time. (2) Mixing known volumes of blood and poison solutions in small 
test-tubes and observing in which series of tubes hemoglobin was dissolved. 
Care was taken to have solutions isotonic or slightly hypertonic. It was 
found that cobra venom has marked hemolytic powers upon bloods of various 
kinds of animals as well as man, and that these powers could be checked in 
the test-tube by the addition of the antivenomous serum. Antivenomous 
serum, alone, has the power to inhibit the haemolysis. All other sera tried 
were without effect. ‘They also found that relationship held good for mul- 
tiples of these numbers. The proportions varied with different bloods. 
In endeavoring to determine whether there might be some relationship 
between the neutral point im vitro and the protective power of the antivenin 
in corpore, they found that, for a guinea-pig weighing 250 to 300 gm., 0.0001 
gm. of cobra venom was the minimal lethal dose, death ensuing in 5 to 8 
hours. ‘Che haemolytic action of this poison was neutralized by o.1 c.c. of 
isotonic antivenin, and such a mixture they found was never fatal to animals, 
but if the hemolytic action was completely neutralized the guinea-pig might 
or might not die. When, however, larger quantities of the venom, completely 
neutralized as regards haemolysis, were used, they were found to be rapidly 
fatal on injection, 5 out of 6 animals dying. ‘Thus the investigators conclude 
that there is no positive connection between the neutralization and the hemo- 
lytic and toxic actions of the venom. ‘Their results are summarized thus: 
(1) Cobra poison is strongly haemolytic in vitro. 
(2) This action is neutralized by antivenomous serum, and the action of 
the latter is specific. 
(3) For certain doses (o.ocor gm.) the measure of this neutralization i 
vitro is a neutralization in cor pore for guinea-pigs. 
(4) This neutralization is chemical, not cellular or vital. 
In a subsequent communication’ on the same subject, Myers and Stephens 
state that poison solutions containing from 0.002 to 0.0075 gm. in I C.C. 
hemolyze blood not at all; at other times, less completely than weaker solutions 
do. Dog’s blood is found to be exceedingly sensitive to the poison, haemolysis 
in this animal occurring in very dilute solution —for instance, in the strength of 
0.5 C.C. = 0.000009 gm. Further, with regard to dog’s blood (and the same 
holds good for frog) it was observed that the haemolysis was often complete in 
less than an hour in solutions of various strengths, while in the corresponding 
tubes for guinea-pig and man hemolysis was not apparent for three to four 
hours, though eventually complete. 
In continuation of the investigations which he commenced with Myers, 
Stephens* made another valuable contribution to our knowledge as to the 
1 Stephens and Myers. The action of cobra poison on the blood. A contribution to the study of 
passive immunity. Jour. of Pathol. and Bacteriol., 1898, V, 279. 
2Stephens. On the hemolytic action of snake toxins and toxic sera. Jour. of Pathology and Bac- 
teriology, 1900, VI, 273. 
