BACTERIAL POISONS. 187 



theria, although the condition in the throat may be one of severe 

 inflammation, it is of itself insufficient to explain the profound 

 prostration and other symptoms of general poisoning which 

 the case manifests. 



Bacterial poisons may be diffused through the culture- 

 medium or they may be retained in the bodies of the bacteria. 

 Consequently, they are classed as extraceHular and intracell- 

 ular. Intracellular poisons are called endotoxins. In cultures 

 of the diphtheria and of the tetanus bacilli the culture-medium 

 contains the poison, and injections of the broth in which these 

 organisms have been grown produce these diseases just as 

 promptly and effectually as injections of the bacteria themselves. 

 Even when the bacteria in these cultures are entirely removed 

 by filtration through porcelain filters, the filtrate reproduces the 

 diseases with all their symptoms just as characteristically as 

 the unflltered cultures. The toxin from the diphtheria bacillus 

 and that from the tetanus bacillus are therefore extracellular 

 toxins, and these two are the only ones which are extracellular 

 as far as is yet known. On the other hand, endotoxins are not 

 liberated into the culture-medium. They are only set free by 

 breaking up the cells, either mechanically, by grinding in a mor- 

 tar, or by disintegration in some other way. The disintegration 

 of these bacteria in the animal body is probably the way in 

 which certain of them cause disease. Typhoid bacilli and chol- 

 era spirilla probably act in this way. 



Tracy* obtained a strong toxin by disintegrating B. prodigio- 

 sus in various ways. 



It seems probable that some bacteria do not produce either 

 intra- or extracellular toxins in the strict meaning of the word. 

 Anthrax bacilli and tubercle bacilli are of this sort. 



The first bacterial poisons to be studied thoroughly were 

 the ptomaines. The observation that the poisonous effects 

 which follow the injection into animals of certain ptomaines 



*Journ. Med. Research. Vol. XVI., No. 2, 1907. pp. 307-327. 



