BACTERIOLYSIS AND ALLIED PHENOMENA 203 



added bactericidal substances, a new danger is involved that of 

 the liberation of a large amount of endotoxin. This substance 

 we believe not to be liberated when bacteria are dissolved within 

 the leucocytes, but to be set free when extracellular solution takes 

 place. The essential fever of the early stages of typhoid fever 

 is very probably due to the endotoxin set free by the solution 

 of the bacilli in the circulating Iplood, and any sudden addition to 

 this amount occurring before the tissues have become immunized 

 or trained to produce anti-endotoxin may be fraught with danger. 

 There can be little doubt that if sero-therapy has any future 

 triumphs in store, they will be in the direction of the production 

 of anti-endotoxins. 



The various antibacterial sera in common use are considered in 

 the last section. 



