NEUTRALISATION OF VENOM BY ANTITOXIN 257 
Now, the antiproteolytic action is easily determined by means 
of a series of test-tubes containing the same quantity of 20 per 
cent. gelatinised bouillon, rendered imputrescible by the addition 
of a small quantity of thymol. The gelatine being kept liquid in 
the incubating stove, a progressively increasing quantity of serum 
is poured into each tube. The same dose of venom, say 1 milli- 
gramme, is then added in each case. The tubes are placed in the 
stove for six hours at 386° C. They are then withdrawn and 
immersed in a bath of cold water. Those in which the gelatine 
solidifies are noted, and thus we establish the dose of antivenomous 
serum that inhibits the proteolysis of this substance. 
These different methods of control enable us to verify the 
activity of antivenomous serums with great exactness, without 
the necessity of having recourse to experiments upon animals. 
In a very important memoir on the reconstitution of the toxins 
from a mixture of toxin + antitoxin, J. Morgenroth' has shown 
that the venom, after being naturalised by the antivenomous 
serum, can be dissociated from its combination by means of a 
method which consists in adding to the latter a small quantity 
of hydrochloric acid. 
Previous experiments by Kyes had established :— 
(1) That antivenomous serum, the antitoxic action of which is 
so manifest when it is mixed tm vitro with cobra-venom, remains 
entirely inert when brought into contact with the combination 
lecithin + venom, that is to say, with cobra-lecithide. 
(2) That the addition of lecithin to a neutral combination of 
venom + antivenomous serwm does not set the venom free again, 
and that under these conditions no lecithide is formed. 
If, in a neutral mixture of cobra-hemolysin and antitoxin we 
could succeed in dissociating the two constituent elements, and 
in then making the cobra-hæmolysin combine with the lecithin, 
! Berliner klinische Wochenschrift, 1905, No. 50. 
jy 
