168 VENOMOUS SNAKES AND THE PHENOMENA OF THEIR VENOMS 
center in the medulla oblongata. Myers called the first cobralysin and the 
second cobranervin. ‘The reasons for their independent existence were first 
furnished by the experiments of Mitchell and Reichert,! who found that 
the hemolytic principles are precipitated and destroyed by heat before the 
nerve poison is affected. The second reason is deduced from the fact that 
the fatally acting principles are set free in a considerable amount when 
multiple doses of cobralysin are completely neutralized by antivenin. It is 
only for the minimal lethal dose, or a little over (using guinea-pigs as test 
animals), that the neutralizations of the two effects run hand in hand. The 
third reason is that the susceptibility, im vitro, of the red corpuscles of 
various animals bears no relation to the susceptibility of those animals to 
subcutaneous inoculation of the venom. 
In this series of study Myers adopted Ehrlich’s* famous fractionated satura- 
tion method‘ for diphtheria toxin-antitoxin to analyze the combining prop- 
erty of cobralysin for anticobralysin. The selection of suitable blood for 
estimating the haemolytic power of cobra was by no means an easy task, for 
the corpuscles of the most susceptible animals (namely, guinea-pig and dog) 
were often hemolyzed by the horse serum alone, rendering the determina- 
tion of the true action of the venom extremely difficult. The corpuscles of 
rabbit were more resistant than these two specimens, but much more venom 
was necessary to obtain enough reaction, and this again made it inconvenient, 
as the antihemolytic power of the antivenin he had in hand was so weak 
that it required 1 to 2 c.c. to counteract the hemolytic effect produced by 
0.001 gm. Myers finally came to use human blood, which, when suspended 
in 1 c.c. of isotonic (0.8 per cent) saline solution, was hemolyzed by 0.000003 
to 0.000005 gm. in 2 hours at 15°C. It was found that the hemolytic action 
of o.cor gm. of dried venom was neutralized by 1.3 c.c. of the antivenin. 
Theoretically the addition of one-thirteenth of this amount of the serum 
0.001 0.001 
should neutralize =;- gm., and the second fraction again another “3 gm. and 
so forth. But, in reality this was found not to be the case. The first frac- 
tion, instead of neutralizing the theoretical portion of the venom on gm., 
neutralized o.cor X 0.8, leaving only o.cor X 0.2 gm. still in the fluid 
unneutralized. Speaking of the hemolytic units, o.cor gm. contained 2,000 
units, but after the addition of 0.1 c.c. of the antivenin only 4oo units were 
found to be present in the mixture, whereas it should, theoretically, neutralize 
only a“ = 153 units by this fraction. The addition of 0.2 c.c. of the anti- 
venin left 200 units, 0.4 c.c. 125 units, 0.6 c.c. 58.8 units, 0.8 c.c. 20 units, 
etc. Finally 1.3 c.c. left a dose less than 1 unit of cobralysin. 
These paradoxical phenomena, first seen by Ehrlich and then by Madsen 
with other toxins, led Myers to assume that cobralysin consists of a set of 
substances whose toxic effect can not be observed, but have an antitoxin- 

1 Weir Mitchell and Reichert. Smithsonian Contrib. Knowl., Washington, 1886. 
2 Stephens and Myers. Jour. of Pathol. and Bacteriol., 1898, V, 279. 
8 Ehrlich. Die Wertbestimmung des Diphtherieheilserums. Klin. Jahrb., 1897, VII, 299; and Ueber 
die Constitution des Diphtheriegiftes. Deut. med. Wochenschr., 1898, XXXVIII, 597- 
4 Madsen. La constitution du poison diphthérique. Ann. Inst. Pasteur, 1899, XIII, 568. 
