EXPERIMENTAL INOCULATION. 385 



be communicated to animals by any of the usual methods 

 of inoculation, 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 cul- 

 ture. The other animals mentioned require larger doses, 

 and death does not occur so rapidly. The symptoms 

 generally are those of the natural disease, the spasms 

 beginning in the muscles nearest the site of inoculation. 

 After death there is found slight hyperaemia 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 acknowledges that in these 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 toxines 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 temperature of 

 80 C. The latter treatment not only killed all the bacilli, 

 but, as we shall see, was sufficient to destroy the activity of 

 the toxines. When such splinters are introduced subcutan- 

 eously, 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 toxines 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 without 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 (v. infra] .] By such experiments, 

 supplemented by the culture experiments mentioned, the 



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