TETANUS 119 



isolated and studied ; possessing, according to Kitasato, the following 

 peculiarities. When cultures of the tetanus bacillus are filtered through 

 porcelain, the filtrate contains the soluble poison, which when injected 

 into animals causes tetanus. Animals inoculated with pieces of the 

 organs of animals dead from the action of the tetanus poison are 

 unaffected ; but inoculation with the blood or pleural exudates produces 

 positive results. The poison is therefore largely present in the circulating 

 fluids. 



Vitality. The greatest amount of poison is produced in fresh, 

 neutral bouillon very slightly alkaline in reaction. The poison loses its 

 activity when exposed for Ij hours to 55 C., twenty minutes to 60 C., 

 and five minutes to 65 C. When dried at the temperature of the body 

 with access of air, the poison is destroyed ; but dried at ordinary room 

 temperature, or at a similar temperature in the desiccator over sulphuric 

 acid, it is not destroyed. Diffuse daylight diminishes the virulence of 

 the poison. Its intensity is preserved for a much longer time when 

 kept in the dark. 



Direct sunlight destroys its poisonous properties in from fifteen to 

 eighteen hours. 



When diluted with a fixed amount of water or bouillon its activity 

 is not diminished. 



Mineral acids and strong alkalies lessen its intensity. 

 In man tetanus is a toxic disease the same as in animals, the bacilli 

 never being found in the blood or organs, but localised at the point of 

 inoculation, and lymph-glands associated with the seat of infection. 

 The period of incubation ranges between one and twenty-two days ; in 

 a case of wound infection at a laboratory the incubation period was four 

 days. The shorter the time between the infection and the appearance 

 of tetanus, the more pronounced is the course of the disease, and the 

 worse the prognosis. 



In cases where the incubation period of the disease was one to ten 

 days, only about 3 per cent, recovered. When the period of incubation 

 was ten to twenty-two days 25 per cent, recovered, and by longer periods 

 of incubation as high as 50 per cent, recovered. 



Immunity and Cure of Tetanus -with Antitetanic Serum in 

 Animals. Behring produced immunity in mice with bouillon cultures 

 of tetanus bacilli weakened by adding trichloride of iodine. Fedorf 

 also prepared a tetanus antitoxin in a dry form from blood serum. 

 Antitetanic serum can also be obtained from horses immunised 

 against tetanus in a similar manner to that employed in the produc- 

 tion of diphtheria antitoxin. The animal selected is a young horse 

 in good condition, which is first tested with mallein and then with 

 tuberculin to ensure its freedom from glanders and tuberculosis. 



