460 Tetanus 



hood of the inoculation but soon becoming general. Death 

 follows sometimes in a very few hours. In rabbits, guinea- 

 pigs, mice, rats, and other small animals the period of 

 incubation is from one to three days. In man the period 

 of incubation varies from a few days to several weeks. 

 It averages about nine days. 



The disease is of much interest because of its purely 

 toxic nature. There is usually a small wound with a slight 

 amount of suppuration and at the autopsy the organs of the 

 body are normal in appearance, except the nervous system, 

 which bears the greatest insult. It, however, shows little else 

 than congestion either macroscopically or microscopically. 



The conditions in the animal body are in general un- 

 favorable to the development of the bacilli, because of the 

 loosely combined oxygen contained in the blood, and they 

 grow with great slowness, remaining localized at the seat 

 of inoculation, and never entering the blood. Doubtless 

 most cases of tetanus are cases of mixed infection in which 

 the bacillus enters with aerobic bacteria, which aid its 

 growth by absorbing the oxygen in the neighborhood. The 

 amount of poison produced must be exceedingly small and 

 its power tremendous, else so few bacilli growing under 

 adverse conditions could not produce fatal toxemia. The 

 toxin is produced rapidly, for Kitasato found that if mice 

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

 the subcutaneous tissues around the inoculation afterward 

 either excised or burned out, the treatment would not save 

 the animal unless the operation were performed within 

 an hour after the inoculation. 



Some incline to the view that the toxin is a ferment, 

 and the experiments of Nocard* might be adduced in 

 support of the theory. He says: "Take three sheep with 

 normal tails, and insert under the skin at the end of each 

 tail a splinter of wood covered with the dried spores of the 

 tetanus bacillus; watch these animals carefully for the first 

 symptoms of tetanus, then amputate the tails of two of 

 them 20 cm. above the point of inoculation, . . . the 

 three animals succumb to the disease without showing any 

 sensible difference." 



The circulating blood of diseased animals is fatal to 

 susceptible animals because of the toxin which it contains; 



* Quoted before the Academic de Medicine, Oct. 22, 1895. 



