548 BACTERIOLOGY. 
pulmonary forms, the latter being known as “¢ wool- 
sorter’s disease.’’ 
Owing to the fact that anthrax was the first infec- 
tious disease which was shown to be caused by a specific 
micro-organism, and to the close study which it received 
in consequence, this disease has probably contributed 
more to our general knowledge of bacteriology than 
any other infectious malady. 
Pollender observed in 1849 that the blood of animals 
suffering from splenic fever always contained minute 
rod-shaped bacteria. Davaine, in 1863, announced to 
the French Academy of Sciences the results of his in- 
oculation experiments, and asserted the etiological rela- 
tion of the micro-organism to the disease with which 
his investigation showed it to be constantly associated. 
For a long time this conclusion was energetically op- 
posed until, in 1879, Pasteur, Koch and others estab- 
lished its truth by obtaining the bacillus in pure cultures 
and showing that the inoculation of these cultures pro- 
duced anthrax in susceptible animals as certainly as did 
the blood of an animal recently dead from the disease. 
Morphology, Slender, cylindrical, non-motile rods, 
having a breadth of 1p to 1.25, and ranging from 2 
or 3u to 20 or 25u in length. They vary thus very 
much in their length. Sometimes short, isolated rods 
are seen, and, again, shorter or longer chains or threads 
made up of several rods joined end to end. In suitable 
culture media very long, flexible filaments may be 
observed, which are frequently united in twisted or 
plaited, cord-like bundles. (See Fig. 71 and Fig. 13, 
p- 47, and Fig. 17, p. 207.) These filaments in hang- 
ing drop cultures, before the development of spores, 
appear to be homogeneous or nearly so; but in stained 
