IMMUNITY STUDIES ON ANTHRAX SERUM 
By A. Eichhorn, Chief, W. N. Berg, Physiologist , and R. A. KEESER, Veterinary 
Inspector , Pathological Division , Bureau of Animal Industry t United States 
Department of Agriculture 
INTRODUCTION 
Beginning with the classical work of Pasteur (9) 1 in 1881, wherein he 
conclusively showed that it was possible through the use of attenuated 
cultures of Bacill%s anthracis to immunize animals against otherwise 
fatal doses of anthrax organisms, various investigators have from time 
to time taken up work along this line and through extensive experi¬ 
mentation have contributed much toward our knowledge of anthrax, 
its treatment, and methods of immunization against it. 
While in general Pasteur's vaccine proved highly satisfactory and 
has been extensively used with excellent results, it has a number of 
disadvantages—that is, it requires two handlings of the animals; the 
desired degree of immunity is not reached until approximately a week 
or 10 days after the injection of the second vaccine; there is a small 
percentage of losses in vaccinated animals due directly to the vaccine; 
and the keeping qualities of the vaccine under unfavorable conditions 
are not the best (4). These factors led a number of investigators to 
attempt various modifications of Pasteur's method. It being possible 
to immunize susceptible animals against anthrax, some workers directed 
their efforts toward the preparation of an immune serum through 
hyperimmunization. Thus, in 1895 Marchoux (8), by immunizing sheep 
according to Pasteur's method and then hyperimmunizing them through 
injections of increasing doses of virulent anthrax culture, succeeded in 
preparing a serum capable of producing a passive immunity in sus¬ 
ceptible animals. Further work along this line was conducted by 
Sclavo, Sobernheim, Mendez, Detre, Carini, and Ascoli. These investi¬ 
gators, however, employed larger animals, especially horses, and suc¬ 
ceeded in producing potent immune serums. Serum of this type was 
found to be of considerable value in cases of threatening infection or 
where anthrax had already made its appearance in a herd, and in the 
treatment of the disease. The immunity conferred by anthrax serum, 
however, is of short duration, lasting only a few weeks. To produce a 
more lasting immunity Sobernheim (10) recommended a simulta¬ 
neous treatment with serum and vaccine, the vaccine corresponding to 
Pasteur's second vaccine. Eichhorn (4) obtained good results from the 
use of serum and spore vaccine and found the method to possess advan¬ 
tages over the Pasteur method. Numerous experiments undertaken 
1 Reference is made by number to “Literature cited,” p. 56. 
Journal of Agricultural Research, 
Washington, D. C. 
et 
(37) 
Vol. VIII, No. a 
Jan. 8,1917 
Key No. A—37 
