ON SPECIFIC THERAPEUTICS. 77 



the snake-venom lecithide. This lecithide would 

 appear to be a pure fatty substance, being 

 soluble in chloroform and even in toluol and 

 alcohol, but as a matter of fact it contains, 

 as I was before able to show you, a very slight 

 quantity of the poison in chemical combination. 

 And it is this portion which induces the bio- 

 logical reaction. The fact that in spite of this 

 component being of a non-fatty nature, the com- 

 pound apparently behaves like an ordinary fat, 

 is due to the presence in it of a great number of 

 fatty molecules which have given to the whole 

 substance their specific characters. 



I have frequently laid stress upon the fact 

 that many nutrient substances are not present 

 in the cells in a free state, and that, therefore, 

 they are not at the disposal of any invader, but 

 that a struggle is always necessary before they 

 can be rendered accessible. In the case of 

 snake venom I have shown that we are dealing 

 with a simple difference between two chemical 

 avidities. In the case of bacteria the affair may 

 be rather more complicated, according to the 

 occurrence of either of two possibilities, viz. : 

 (i) A direct assimilation in consequence of a 

 higher degree of affinity, or (2) an indirect 

 action by injury to the cell. Supposing, for 



