106 ANTHRAX 
Anthrax is to be differentiated from certain specific diseases such as 
symptomatic anthrax (black leg), malignant edema, and septicemia 
hemorrhagica. Rabies is not infrequently mistaken for anthrax. 
These diseases can as a rule be readily diagnosed by the methods 
applicable to each. In addition to the specific infections, anthrax has 
been confused with certain dietary troubles and poisoning. 
Protective inoculation. Toussaint was the first to make use of 
protective inoculations in anthrax. He heated defibrinated blood to 
a temperature of 55° C. for 10 minutes. Better results were obtained 
by heating the blood to 60° C. for 3 or 4 times before using it. Pasteur, 
however, was the first to prove that immunity could be obtained by 
the use of cultures of attenuated bacteria. Several methods of 
attenuating the specific organisms were proposed by Pasteur, Tous- 
saint, Chaveau, Chamberland, Arloing and others. 
Pasteur’s method consists in inoculating the animal with a small 
quantity of culture which has been grown at a high temperature— 
42 to 43° C.—_for several days. This deprives the bacteria of their 
virulence. To strengthen the resistance, the animals are again 
inoculated 12 days later with a stronger virus.* After the two inocu- 
lations, they are said to be protected against the most virulent an- 
thrax; but the immunity is of short duration. Chamberland reported 
in 1894 that a total of 1,988,677 animals were treated by this method 
in France, and that the loss from anthrax had diminished from 10 per 
cent. in sheep and 5 per cent. in cattle to less than 1 per cent. Cope, 
in his report to the English Board of Agriculture, regards the con- 
clusions of Chamberland as somewhat fallacious, because in order to 
prove that the animals inoculated received immunity, it should be 
shown that they were subsequently exposed to the risks of natural 
infection. The excellent work which has been done by Neal and 
Chester, at the Delaware College Experiment Station, has shown the 
possible efficiency of this method. Of the 331 cows which they vac- 
cinated against anthrax, two died of the disease, giving a death rate 
of less than 1 per cent. and this in a territory so saturated with the 
virus that it was practically impossible to keep cattle at all before its 
*The first vaccine is a culture of anthrax bacteria that has been cultivated so that 
it will kill mice but has no ill effect on rabbits and sheep. The second vaccine, given 
12 days later, is more virulent. It will kill mice and guinea-pigs and occasionally 
rabbits. Immunity is established 12 days after the second inoculation. 
The French recommend the following plan of injection. The first vaccine is injected 
into the internal surface of the right thigh and the second into the internal surface of the 
left thigh. The vaccine should be used as soon as it is procured. A contaminated 
vaccine should not be injected. 
