The Antagonism between Toxins and Antitoxins. 427 



Protocols. 



A. EXPERIMENTS WITH DIPHTHERIA TOXIN. 



t 



I. Experiments to ascertain whether the Toxin of Diphtheria passes 

 through a Gelatin Filter. 



The toxins were prepared bj the method stated above and filtered 

 through a Pasteur-Chamberland filter to free them from bacilli. 

 The minimal fatal dose calculated for one kilogram weight of 

 guinea-pig was 0*12 c.c. of toxin No. 1, and 0*6 c.c. of toxin No. 2. 

 Portions of each of these toxins were filtered through gelatin and 

 afterwards injected into guinea-pigs. As seen below the filtrates in 

 each case contained toxin, but in less amount than the original 

 solutions.* 



Toxin No. 1. 



Toxin No. 2. 



* This small diminution in toxic power by filtration may possibly be due to the 

 action of oxygen at high, tension (50 atmospheres of compressed air) or to the 

 size of the toxin molecule being of the order of the molecular size of albumoses. 

 Albumoses, as shown by one of us (' J. Physiol.,' 1896), pass through gelatin, but 

 le?s readily than water, and the filtrate is accordingly less concentrated than the 

 original solution. 



VOL. LXIII. 2 K 



