TETANUS BACILLUS 169 



end, which is either round or oval. At times, the bacilli in chains 

 sporulate. The organism is motile; possesses numerous flagella 

 (from fifty to a hundred) peritrichously arranged; stains well with 

 all the common basic aniline dyes, and retains the color in Gram's 

 method. (Fig. 58.) 



Oxygen Requirements. Strictly anaerobic when freshly iso- 

 lated from earth or wounds, but, after long cultivation on culture 

 media, it becomes more tolerant to small amounts of oxygen. 



Temperature. Grows best at 37 C. Below 14 C. not at all. 



Vital Resistance. Spores resist 80 C. for an hour. This fact 

 enabled Kitasato to kill all other organisms, except their spores, in 

 pus. Six days' exposure to direct sunlight is needed to kill the 

 spores. The thermal death-point is best considered as 100 C. 

 for i hour. They are killed in 2 hours by 5 percent phenol +.5 

 percent HC1 and in 30 minutes by i-iooo HgCl 2 + .5 percent HC1. 



Chemical Activities. Ferments sugar; produces gas, indol, 

 alkali, and H 2 S. which gives to the culture an odor of burnt garlic or 

 onion; marsh gas, CO 2 , and nitrogen are produced. Gelatine is 

 liquefied. The most important product of growth is the highly 

 poisonous complex toxin, which is made up of tetanolysin, and 

 tetanospasmin; the latter has a great affinity for nerve tissues. This 

 toxin is soluble in water, and can be separated from it by means of 

 ammonia sulphate. 



Habitat. Is found in garden soil, hay, manure, and dust. 

 Has been found in cobwebs, on weapons, in cartridges, and in the 

 feces of man and of animals. It is said to have been found in the 

 spinal cord of a man who did not die of tetanus. It has also been 

 isolated from bronchi in a case of rheumatic tetanus in which there 

 was no lesion in the body (Carbon and Perrors). In disease 

 it is found in the infected wound, generally in a deeply punctured 

 one, which is usually purulent and contains but few bacilli. Puer- 

 peral tetanus, and tetanus of the new-born, are but varieties of the 

 disease, dependent upon the site of infection, whether of the pla- 

 centa or umbilical cord. Tetanus sometimes occurs spontaneously, 



