TETANUS BACILLUS 189 



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 iooC. 

 for one hour. They are killed in two hours by 5 percent phenol 

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

 -f .5 percent HC1. 



Chemical Activities. Ferments sugar; produces gas, indol, 

 alkali, and H^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 

 faeces of man and of animals. It has 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 puru- 

 lent and contains but few bacilli. Puerperal tetanus, and tetanus 

 of the new-born, are but varieties of the disease, dependent upon 

 the site of infection whether of the placenta or umbilical cord. 

 Tetanus sometimes occurs spontaneously, without a sign of injury 

 anywhere. Sheep and goats are susceptible to infection, so. are 

 guinea pigs and rabbits. Horses are peculiarly susceptible. Soil, 

 or manure, getting into wounds, is often a cause of tetanus. Cow- 

 dung poultices, mud dressings, or cobweb applications to stop 

 haemorrhages, have also caused the disease. Tetanus following 

 vaccination may be due to infected virus, the latter becoming in- 

 fected from the faeces of the vaccine-producing cows but more 

 commonly is due to dirt getting into vaccination wounds. 



Cultures. This organism is difficult to grow, and always 

 requires an atmosphere of hydrogen. 



