SPECIAL BACTERIOLOGY 
163 
It was discovered by Pollender in 1849, and thoroughly 
studied by Davaive in 1863. (See Fig. 31.) 
The bacillus is a very long rod, 5 to 10 /x long. It 
occurs singly in blood, but grown on artificial cultures, 
is found in long threads. It has spores and is Gram¬ 
positive. A capsule is seen occasionally (never when 
grown on artificial media). The anthrax is an aerobic 
organism, facultatively anaerobic, and grows well on or¬ 
dinary culture media. It is nonmotile, lias no flagella. 
Spore formation ceases below 18° C. and above 42° C. 
Fig. 30.—Bacillus welchii. Film preparation of a milk culture, x 1000. 
(Hewlett —Manual of Bacteriology.) 
Because of its spores the anthrax bacillus is very re¬ 
sistant to heat and ordinary chemicals, it takes 10 min¬ 
utes’ exposure to live steam to kill them. 
In man three varieties of infection are produced: (1) 
skin (“the w T ool sorters’ disease”), (2) lungs, and (3) 
gastrointestinal. No other disease shows so many bacilli 
in blood as the anthrax infections. It produces an endo¬ 
toxin. Pasteur’s vaccine is a wonderfully efficient treat¬ 
ment of the infection in the cattle (the cultures for the 
