249 BLACK LEG 
infected artifically and they have been observed affected with it about 
packing houses. Guinea pigs are very susceptible to inoculation. It 
is reported that horses, asses and white rats develop local lesions when 
inoculated subcutaneously with the virus. Other animals seem to be 
immune. In cattle, it rarely occurs in the very young, under six 
months, and in adults after the fourth year. Katona reports its 
appearance in calves three to four weeks of age and in cattle seven and 
eight years old. 
Infection takes place through wounds in the skin, and presumably 
the digestive tract and trachea. The disease occurs usually in the 
summer months. The influence of the site of inoculation is said to 
be very marked. According to Besson, the dose of bacilli that will 
kill a cow inoculated in the cellular tissues of the body will cause 
merely a benign swelling if injected into the connective tissue of the 
neck. The intravenous inoculation leads to a slight rise of tempera- 
ture only. In rabbits the disease can be produced if the inoculation 
is accompanied by M. prodigiosus or the site of injection traumatized. 
History. It is supposed that black quarter has existed for hundreds 
of years, although it was not until late in the last century that it was 
positively differentiated and recognized as a distinct and specific 
disease. The descriptions given to many of the earlier epizodtics 
designated as anthrax correspond more exactly with the present 
knowledge of black quarter than they do of anthrax. 
In 1782, Charbert classified the various anthracoid diseases recog- 
nized at that time into three groups, (1) anthrax fever, where the 
disease manifested itself without external swelling, (2) true anthrax, 
where the lesions consisted at first of small, hard and very painful 
swellings followed or accompanied by fever and other general symp- 
toms, and (3) symptomatic anthrax, where the swelling was preceded 
by a rise of temperature, loss of appetite and symptoms of general 
depression. This classification was held for nearly a century. 
Boutrolle, in 1797, refers to a disease which he called mal de cuisse 
(quarter evil) because it affected the animal in the thigh. Viborg 
described the disease in Denmark, where it has long been known to the 
laymen and designated by them as raslesyge (“rattle disease”). Its 
clinical features were very accurately described by Walraff in 1856. 
In 1879, Arloing, Cornevin and Thomas proved the causal relation of a 
certain microérganism to this disease and thus established its specific 
nature. A year later (1880) they described the specific microérganism 
