28o PATHOGENIC BACTERIA. 



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 

 either excised or burned out, this 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, quoted before the Acad- 

 mie de Me*decine, October 22, 1895, 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 care- 

 fully for the first symptoms of tetanus, then amputate the 

 tails of two of them 20 cm. above the point of inocula- 

 tion, . . . the three animals succumb to the disease with- 

 out showing any sensible difference.' 7 



The circulating blood of diseased animals is fatal to 

 susceptible animals because of the toxin which it con- 

 tains; and the fact that the urine is also toxic to mice 

 proves that the toxin is excreted by the kidneys. 



From pure cultures of tetanus bacilli grown in various 

 media, and from the blood and tissues of animals affected 

 with the disease, Brieger succeeded in separating two 

 alkaloidal substances "tetanin" and u tetano- toxin, " 

 both very poisonous and productive of tonic convulsions; 

 and Brieger and Frankel later isolated an extremely poi- 

 sonous toxalbumin. 



