TETANUS. 
381 
traumatic, rheumatic, idiopathic ; and each of these forms of 
disease was ascribed to different causes. It was not, however, 
until the researches of Nicolaier that the real cause of tetanus 
was discovered. Nicolaier’s first announcements were published 
in 1884, and they were amply supported and confirmed by the 
researches of Kitasato, published in 1889. Kitasato was success¬ 
ful in isolating and in growing, in pure cultures, the tetanus 
bacillus, and he proved by the inoculation of animals that the 
disease could actually be produced by the bacillus that he had 
isolated and described. 
The tetanus bacillus is an organism of rather peculiar shape. 
It is rather long and slender, and has a round enlargement at 
one end, which contains a spore. This bacillus has been found 
in earth, in pus, in manure, and in the secretion from infected 
wounds. The bacillus is isolated in the laboratory with much 
difficulty, because it will only grow where there is an absence of 
oxygen. 
The spore of the tetanus bacillus is quite resistant, very much 
more so than the bacillus itself, and it requires heating at boil¬ 
ing temperature from two to five minutes to destroy it. The 
isolation of the germ in the laboratory is based upon this char¬ 
acteristic, and is carried out after the method first described and 
employed by Kitasato. A small quantity of the material to be 
examined is exposed for an hour at a temperature of 80° C., and 
in this way all of the bacteria and most of the spores in the sub¬ 
stance, with the exception of the spores of tetanus, are destroyed, 
and the inoculation of culture media with material so treated 
enables one to obtain a pure culture of the tetanus bacillus 
without much further difficulty. The tetanus bacillus, and par¬ 
ticularly its spores, is not only resistant to heat, but to other 
conditions that are unfavorable to the growth of germs. For 
instance, it requires exposure to a 5 per cent, creolin solution for 
five minutes or to 5 per cent, carbolic acid solution for ten hours 
to destroy it. A 5 per cent, carbolic acid solution, together with 
0.5 per cent, of hydrochloric acid, destroys these organisms in 
twenty-five minutes. A particularly strong antiseptic for the 
