436 TETANUS 



(6) The Artificially produced Disease. The disease can be 

 communicated to animals by any of the usual methods of inocula- 

 tion, but does not arise in animals fed with bacilli, whether 

 these contain spores or not. Kitasato found that pure cultures, 

 injected subcutaneously or intravenously, caused death in mice, 

 rats, guinea-pigs, and rabbits. In mice, symptoms appear in a 

 day, and death occurs in two or three days, after inoculation 

 with a loopful of a bouillon culture. The other animals 

 mentioned require larger doses, and death does not occur so 

 rapidly. Usually in animals injected subcutaneously the spasms 

 begin in the limb nearest the point of inoculation. In the 

 case of intravenous inoculation the spasms begin in the 

 extensor muscles of the trunk, as in the natural disease in man. 

 In intraperitoneal injection spasms in the muscles controlled by 

 the splanchnic system are an outstanding feature. After death 

 there is found slight hypersemia without pus formation, at the 

 seat of inoculation. The bacilli diminish in number, and may 

 be absent at the time of death. The organs generally show 

 little change. 



Kitasato stated that in his earlier experiments the quantity of 

 culture medium injected along with the bacilli already contained 

 enough of the poisonous bodies formed by the bacilli to cause 

 death. The symptoms came on sooner than by the improved 

 method mentioned below, and were, therefore, due to the toxins 

 already present. In his subsequent work, therefore, he employed 

 splinters of wood soaked in cultures in which spores were 

 present, and subsequently subjected for one hour to a tempera- 

 ture of 80 C. The latter treatment not only killed all the 

 vegetative forms of the organism, but, as we shall see, was 

 sufficient to destroy the activity of the toxins. When such 

 splinters are introduced subcutaneously, death results by the 

 development of the spores which they carry. In this way he 

 completed the proof that the bacilli by themselves can form 

 toxins in the body and produce the disease. Further, if a 

 small quantity of garden earth be placed under the skin of a 

 mouse, death from tetanus takes place in a great many cases. 

 [Sometimes, however, in such circumstances death occurs with- 

 out tetanic symptoms, and is not due to the tetanus bacillus but 

 to the bacillus of malignant oedema, which also is of common 

 occurrence in the soil (vide infra).] By such experiments, 

 supplemented by the culture experiments mentioned, the 

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

 known. 



The Toxins of the Tetanus Bacillus. The tetanus bacillus 



