NEUTRALISATION OF VENOM BY ANTITOXIN 257 



Now, the antiproteohjtic action is easily determined by means 

 of a series of test-tubes containing the same quantity of 20 per 

 cent, gelatinised houillon, 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 stove for six hours at 36' C. They are then withdrawn and 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 in vitro with cobra-venom, remains 

 entirely inert when brought into contact w'ith the combination 

 lecithin -\- venom, that is to say, with cohra-lecithide. 



(2) That the addition of lecithin to a neutral combination of 

 venom -f antivenomous serum does not set the venom free again, 

 and that under these conditions no lecithide is formed. 



If, in a neutral mixture of cohra-h(B?nolysin and antitoxin we 

 could succeed in dissociating the two constituent elements, and 

 in then making the cobra-hcEinolysin combine with the lecithin, 



' Berliner Mininche Wochenschrift, 1905, No. 50. 

 17 



