386 TETANUS. 



natural habitats of the B. tetani, as given above, have become 

 known. 



The Toxines of the Tetanus Bacillus. The tetanus 

 bacillus being thus accepted as the cause of the disease, we 

 have to consider how it produces its pathogenic effects. 



Almost contemporaneously with the work on diphtheria was the 

 attempt made with regard to tetanus to explain the general symptoms 

 by supposing that the bacillus could excrete soluble poisons. Brieger, 

 for instance, in his earlier work recorded that a base tetanin could be 

 isolated from dead cultures, and this, as well as another base called 

 tetanotoxin, was also obtained by Kitasato and Weyl. When injected 

 into animals, these substances produced spasms and death, but though 

 they may have contained the real toxine they were obtained by the 

 earlier faulty methods. 



In 1890 Brieger and Fraenkel announced that they had 

 isolated a toxalbumin from tetanus cultures, and this body 

 was independently discovered by Faber in the same year. 

 Brieger and Fraenkel's body consisted practically of an 

 alcoholic precipitate from filtered culture in bouillon, and 

 was undoubtedly toxic. The toxic properties of bacterium- 

 free filtrates of pure cultures of the B. tetani were in- 

 vestigated in 1891 by Kitasato. He found that when the 

 filtrate, in certain doses, was injected subcutaneously or 

 intravenously into mice, tetanic spasms developed, first in 

 muscles contiguous to the site of inoculation and later all 

 over the body. Death resulted. He found that guinea- 

 pigs were more susceptible than mice, and rabbits less so. 

 In order that a strongly toxic bouillon be produced, it must 

 originally have been either neutral or slightly alkaline. 

 Kitasato further found that the toxine was easily injured by 

 heat. Exposure for a few minutes at 65 C. destroyed it. 

 It was also destroyed by twenty minutes' exposure at 60 C. 

 and by one and a half hours' at 55 C. Drying had no 

 effect. It was, however, destroyed by various chemicals 

 such as pyrogallol and also by sunlight. Behring has more 

 recently pointed out that after the filtration of cultures 

 containing toxine, the latter may very rapidly lose its 

 power, and in a few days may only possess T ^th of its 



