THE BACILLUS OF TETANUS. 439 



sublimate, 1 : 1000, and in thirty minutes by the same 

 solution plus 0.5 per cent, hydrochloric acid. 



Action upon animals. After subcutaneous inocula- 

 tion of mice with minute portions of a pure culture of 

 this organism tetanus develops in twenty-four hours 

 and ends fatally in from two to three days. Rats, 

 guinea-pigs, and rabbits are similarly affected, but only 

 by larger doses than are required for mice: the fatal 

 dose for a rabbit being from 0.3 to 0.5 c.c. of a well- 

 developed bouillon culture. The period of inoculation 

 for rats and guinea-pigs is twenty-four to thirty hours, 

 and for rabbits from two to three days. Pigeons are 

 but slightly, if at all, susceptible. 



The tetanic convulsions always appear first in the 

 parts nearest the seat of inoculation, and subsequently 

 become general. 



At autopsies upon animals that have succumbed to 

 inoculations with pure cultures^ of the tetanus bacillus 

 there is little to be seen by either macroscopic or micro- 

 scopic examination, and cultures from the seat of inocu- 

 lation are usually negative in so far as finding the teta- 

 nus bacillus is concerned. At the seat of inoculation 

 there is usually only a hypersemic condition. In un- 

 complicated cases there is no suppuration. The internal 

 organs do not present any change, and culture-methods 

 of examination show them to be free from bacteria. 

 The death of the animal results from the absorption of 

 a soluble poison, either produced by the bacteria at the 

 seat of inoculation or, which seems more probable, pro- 



1 Animals and human beings that have become infected with this organism 

 in the natural way commonly present a condition of suppuration at the site 

 of infection ; this is probably not due, however, to the tetanus bacillus, but 

 to other bacteria that have also gained access to the wound at the time of 

 infection. 



