42 POISONOUS PROTEINS 



like that following infection with the living or- 

 ganism except that the period of incubation is 

 shortened. There is no longer either opportu- 

 nity or need for the multiplication of the bacil- 

 lus. This has taken place in vitro and enough 

 of the protein to kill has been introduced. One 

 of the features that characterizes and marks the 

 period of incubation has been withdrawn. It 

 only remains for the body cells by means of 

 their secretions to cleave the bacterial protein 

 and set the poison free. The period of incu- 

 bation is reduced half or more, then the evi- 

 dences of poisonous action are exactly the same 

 as in the inoculated animal. The temperature 

 falls at the same rate and autopsy reveals ex- 

 actly the same lesions. The chemotactic pull of 

 the dead protein has proved just as strong and 

 just as violent as that of the living protein. In 

 fact the pull in both instances is a chemical and 

 not a vital one and the lesions result from a re- 

 action between the proteins of the bacterial cells 

 and those of the body cells. 



(c) The Soluble Poison. When a fatal dose 

 of the crude soluble poison is injected into 

 the peritoneal cavity, the effects begin to reveal 

 themselves much sooner. There is now no pe- 

 riod of incubation. Both steps, which have 

 characterized this period, are now omitted. The 



