362 TETANUS. 



apparently come to the conclusion that the toxicity of the 

 toxalbumins originally described by him is due to the 

 presence of a non-proteid body. In his latest paper he 

 describes the isolation, by a special method, of a toxine 

 which is neither peptone, albumin, nor albuminate, and 

 the nature of which is quite unknown. 



Probably a diastase is concerned in the toxic action 

 of the tetanus bacillus. Like a ferment, the toxine is 

 destroyed, as we have seen, by comparatively low tempera- 

 tures, but it may simply be an unstable chemical com- 

 pound, for albuminous bodies not diastatic in nature may 

 be changed at similar temperatures. The liquefaction (i.e., 

 probable peptonisation) of gelatine cultures advances part 

 passu with the development of toxines, and filtered 

 bacterium- free cultures will still liquefy gelatine. It may 

 be, however, that there is developed, in addition, a peptic 

 ferment which will, of course, also pass through the filter. 

 For if equal portions of the filtered culture be left in 

 contact with equal portions of gelatine for various lengths 

 of time, there is no increase of toxicity in those kept 

 longest. There is thus no fresh development of toxine 

 during the advancing liquefaction of the gelatine. Thus 

 peptic digestion and toxine formations may be due 

 to different vital processes on the part of the tetanus 

 bacillus. 



The strongest argument in favour of a ferment being 

 concerned in the toxine production, is derived from the 

 occurrence of a definite incubation period between the in- 

 troduction of the toxine into an animal's body and the 

 appearance of symptoms. This incubation period varies 

 according to the species of animal employed, and the path 

 of infection. In the guinea-pig it is from thirteen to 

 eighteen hours, in the horse five days, and the incubation 

 is shorter when the poison is introduced into a vein than 

 when injected subcutaneously. Further, a dog can receive 

 300 c.c. of a culture of which the fatal dose for a guinea-pig is 

 infinitesimal, without the incubation period being shortened. 

 Certain remarkable results have been obtained by Courmont 



