ETIOLOGY 267 



bacillus stains readily with the aniline dyes, especially with 

 carbolfuchsin. It takes the Gram stain. It grows well in 

 nutrient gelatin, agar or bouillon and on blood serum at the 

 temperature of the body and in an atmosphere of hydrogen or 

 in the absence of air as in deep agar cultures. The addition of 

 a little grape sugar facilitates its growth. It has the distinc- 

 tion of producing the most powerful (poisonous) toxin of any 

 known bacteria, 0.23 of a milligram being estimated as a fatal 

 dose for a man of 175 pounds weight. 



The fact that this bacillus is an anaerobe renders its culti- 

 vation of little practical value in diagnosing the disease. Al- 

 though it is not distributed in the body, it can usually be 

 found in cover-glass preparations, made from the local lesion 

 and stained with carbol fuchsin. 



Bacillus ietani is found in the soil. It has been found in 

 hay dust, in the mortar of old masonry, in the dust in rooms, 

 barracks and hospitals and in the arrow poison of certain 

 savages in the New Hebrides. They obtain it by smearing 

 their arrow heads with mud from crab holes in the swamps. 

 It is reported that certain savages in Africa destroy their 

 enemies by putting bits of broken glass mixed with certain 

 soils in their shoes. The cause of death is tetanus. Mold 

 rich in horse manure seems to be the most favorable abode for 

 it. It has been stated that it exists in all soils. There are 

 good reasons for believing that this is an over-estimate of the 

 wideness of its distribution. It certainly is more numerous in 

 some localities than in others. 



The tetanus bacillus is very resistant, especially in its 

 spore form, to destructive agents such as drying and the 

 ordinary disinfectants. Kitasato found that a 5 per cent solu- 

 tion of carbolic acid applied for ten hours failed to kill the 

 spores. Tizzoni and Cattani found that mineral and organic 

 acids produced no effect upon the dried spores, von Behring 

 found that iodine trichloride possesses a strong antiseptic effect 

 upon them. They are not affected by the gastric fluids. It 

 has been noted by Kitt that the dried spores in pus have 

 retained their virulence for sixteen months. They are de- 



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