TETANUS. 377 



Bacillus tetani. Kamen is of the opinion that the 

 bacilli can grow in the intestine and be absorbed, espe- 

 cially where there are imperfections in the mucosa. It 

 is not impossible, though he does not think it probable, 

 that the bacteria growing in the intestine could elaborate 

 enough toxin to produce the disease by absorption. 



All animals are not alike susceptible to the disease. 

 Men, horses, mice, rabbits, and guinea-pigs are all sus- 

 ceptible ; dogs are much less so. Most birds are scarcely 

 at all susceptible either to the bacilli or to the poison. 

 Amphibians are immune, though it is said that frogs 

 can be made susceptible by elevation of their body- 

 temperature. 



When a white mouse is inoculated with an almost 

 infinitesimal amount of bouillon or solid culture, or is 

 inoculated with garden-earth containing the tetanus 

 bacillus, the disease is almost certain to follow, the 

 first symptoms coming on in from one to two days. 

 The mouse develops typical tetanic convulsions, which 

 begin first in the neighborhood of the inoculation, but 

 soon become general. Death follows sometimes in a 

 very few hours. In rabbits the period of incubation is 

 nearly two weeks, and in man may be three weeks. 



The conditions in the animal body are not favorable 

 for the development of the bacilli, because of the free 

 supply of oxygen contained in the blood, and we find 

 that they grow with great slowness, remain localized at 

 the seat of inoculation, and never enter the blood- or 

 lymph-circulation. Doubtless most cases of tetanus are 

 cases of mixed infection in which the bacillus enters with 

 bacteria, which greatly aid its growth by using up the 

 oxygen in their neighborhood. The amount of poison 

 produced must be exceedingly small and its power tre- 

 mendous, else so few bacilli growing under adverse con- 

 ditions could not produce fatal toxemia. The poison is 

 produced rapidly, for Kitasato found that if mice were 

 inoculated at the root of the tail, and afterward the skin 

 and the subcutaneous tissues around the inoculation were 



