90 ANTHRAX 
disease, which had previously been described as independent affec- 
tions, were all one disease. As late as 1805, Kausch gave a good 
description of anthrax but denied its contagiousness. Delafond and 
Gerlach thoroughly investigated ovine anthrax in 1854 and its con- 
tagiousness was experimentally shown by Gerlach. In 1850, Heu- 
singer published a very comprehensive treatise on anthrax which deals 
at length with its history and geographical distribution. 
Much new information concerning the nature of anthrax was 
acquired during the fifth decade of the last century. In 1855, 
Pollander announced the discovery, which he first made in 1849, of 
minute unbranched rod-shaped bodies in the blood of cattle dead of 
anthrax. Davaine observed similar bodies in 1850. Then followed 
a long series of observations and somewhat contro versial discussions 
on the bacterial origin of the disease, culminating by Robert Koch’s 
careful description of the morphology of its specific organism including 
the spore formation in 1876 (1877 Pasteur). Cohn, however, seems 
to have been the first to have called the organism a Bacillus and to 
have suspected the existence ‘of spores. Toussaint, in 1880, and 
Pasteur in 1881, published results of investigations directed toward 
protective inoculation. Since that time, the literature on the cause, 
morbid anatomy and prevention of anthrax has become very exten- 
sive. 
Geographical distribution. Anthrax is a widely disseminated 
disease. The continent of Europe has perhaps suffered most from 
itsravages. It occurs, also, in Northern, Eastern and Central Africa, 
where in recent years it has become a great plague. In Siberia, it has 
caused fearful destruction, and in that country it is still known as the 
“Siberian Plague.” It has frequently appeared in England. Russia, 
India and Australia are also infected. South America is also reported 
to suffer much from its ravages. It has occurred in the United States 
in many localities. There are very few, if any, countries where this 
disease has not been found. A knowledge of its specific cause, with 
the methods of properly disposing of dead animals, isolation and disin- 
fection, as well as the preventive inoculations now in vogue, have made 
it possible to prevent wide-spread epizodtics. In America it is looked 
upon as a comparatively rare disease, excepting in certain very 
restricted infected districts. 
Etiology. Anthrax is caused by a microdrganism, Bacterium 
anthracis. This organism can usually be found in the diseased organs 
