254 VENOMS 



did not take place until twenty or thirty minutes later, the toxicity 

 of the venom no longer reappeared. 



On the other hand, the admirable researches of Kyes and Sachs, 

 and subsequently those of Morgenroth, pursued under the direction 

 of Ehrlich at the Laboratory of Experimental Therapy at Frank- 

 fort, have proved the readiness of venom to enter into chemical 

 combination with certain elements of normal serums, in particular 

 with lecithin, a combination which results in the formation of 

 h(Bmolysing and non-toxic lecithides, the neurotoxin being left free. 



It therefore seemed impossible to deny the existence of a 

 chemical reaction between the venom and the serum, which was 

 until quite recently considered as proved. We shall see presently 

 that this is not the case. But let us first endeavour to determine 

 the laws that govern the neutralisation of variable quantities of 

 venom by antivenomous serum. 



If, in a series of test-tubes, we bring the same quantity of cobra- 

 venom {e.g., 0*00005 gramme, a dose which is invariably lethal to the 

 mouse in two hours) into contact with progressively increasing 

 quantities of an antivenomous serum {e.g., 001 c.c, 0"02 c.c, &c., up 

 to 0"! c.c), and, after thirty minutes of contact, inject these different 

 mixtures subcutaneously into a series of mice, we find that all 

 those that have received the mixtures containing less than 0'05 c.c. 

 of serum succumb after variable intervals, while all the rest survive. 

 It is evident that, under these conditions, the serum experi- 

 mented upon has shown itself capable of neutralising in vitro, in 

 a dose of 0"05 cc, 5 centimilligrammes of venom. 



The same serum should therefore neutralise 1 milligramme of 

 venom in a dose of 1 c.c, that is to say, that this mixture injected 

 into a mouse ought to be entirely innocuous. Experiments show, 

 however, that in reality it is necessary to mix 1"2 cc. of serum with 

 1 njilligramme of venom in order that the inoculated mouse may 

 not succumb. 



This proves that, in the initial mixture of 0"C0005 gramme of 

 venom + 005 cc of serum, there remained an exceedingly small 



