PATHOGENIC BACTERIA. 329 



culture-media, perferably those containing dextrose. Gelatin 

 is liquefied slowly; the colonies in gelatin present characteristic 

 radiating filaments and look like a bristle brush. It grows on 

 the other culture-media. Gas formation is not pronounced. 



This organism appears to be widely spread in external 

 nature, especially in the soil. It is often found in garden- 

 earth and in the feces of herbivorous animals. It is conse- 

 quently more apt to be encountered in practice in deep, pene- 

 trating wounds caused by dirty nails and the like. McFar- 

 land claims that it may occur in vaccine virus when this is 

 carelessly prepared, and this would explain those rare cases of 

 tetanus which occur after vaccination.* Tetanus bacilli have 

 been found in gelatin, and it is stated that tetanus has followed 

 the injection of gelatin as a hemostatic. The infection ap- 

 pears usually, if not always, to be introduced through some 

 wound, t Clinically, persons having the disease suffer from 

 spasms of the muscles about the neck and the lower jaw (lock- 

 jaw). The spasms finally become general. 



Inoculation with a pure culture produces tetanus in a great 

 many animals. Horses and guinea-pigs, are very susceptible, 

 mice, rabbits, rats are less so in the order named. Sheep, dogs, 

 pigeons and chickens are but little susceptible. The tetanic 

 spasms begin in the vicinity of the point of inoculation and 

 afterward become general. The bacilli are not widely scat- 

 tered through the body; they occur only in the immediate 

 vicinity of .the original lesion, and there are no important mac- 

 roscopic alterations in the internal viscera. 



Tetanus is the type of the purely toxic disease. Its symp- 

 toms may be produced in animals by the injection of liquid 

 cultures which have been deprived of their bacteria by fil- 

 tration. The toxic substance appears not to be a ptomaine, 

 as was at first supposed, and its exact nature is not determined. 



* Journal Medical Research. Vol. VII. 1902. 



t Wells Fourth of July Tetanus. American Medicine. June 13, 1903 



