Microhic Diseases Individually Considered. 291 



or ingested, it must gain entrance to the system 

 through a solution of continuity. 



All wounds are not alike adapted to the growth of 

 the tetanus bacillus ; the germ is anaerobic and conse- 

 quently requires a medium little accessible to atmos- 

 pheric air; besides, it is inofiensive if not protected 

 against the phagocytes by accessory conditions. The 

 production of tetanus, therefore, as a rule, requires 

 deep, anfractuous, contused wounds or those contami- 

 nated by other germs, and more especially by the 

 ordinary pyogenic species. Nevertheless, tetanus has 

 often been observed to follow insignificant wounds. 

 It should be observed that wounds favorable for the 

 growth of the bacillus of tetanus are also favorable 

 for that of the septic vibrio. Now, the bacillus of 

 malignant oedema is also found in tetanogenic earth, 

 so that the same wound may be contaminated with 

 both germs; gangrene, however, running its course 

 more rapidly than tetanus, the latter may only appear 

 after recovery from the former, or may not appear 

 at all if the subject succumbs to the septicaemia 

 (Verneuil). 



The bacillus of tetanus secretes in the wound spe- 

 cial toxines which have a poisonous action on the 

 organism similar to that of strychnine. If a culture 

 of tetanus be tiltered so as to completely separate the 

 microbes from the soluble part, and the latter be in- 

 jected to animals, an absolutely typical tetanus re- 

 sults. This filtered liquid is very toxic : one-twentieth 

 of a drop kills a mouse in thirty-six hours, one drop 

 kills a guinea pig in twenty- four hours. 



The nature of the tetanic poison is yet incom- 

 pletely known in spite of numerous investigations. 



