Jan. 8, 1917 
Immunity Studies on Anthrax Serum 
55 
and so far the writers have found that the complement-fixing value has 
varied with the stage of hyperimmunization—that is, serum from animals 
in the early stages of the hyperimmunization process possesses little or 
no complement-fixing value, while that from animals in the advanced 
stages of the process exhibits considerable complement-fixing properties. 
The writers are hopeful that further work along this line will bear out 
the results thus far obtained. 
Thus it may prove that by applying a known potent anthrax serum as 
a standard for the titration of the antigen and for establishing the mini¬ 
mum amount of serum which will cause complete fixation of complement 
in the presence of the determined amount of antigen, a standard may be 
established which will permit an accurate standardization of anthrax 
serum. 
No fixation of complement occurs with the serum from animals vacci¬ 
nated against anthrax or even after they have received the smaller 
infective doses of virulent culture, a positive reaction occurring only 
after the beginning of the administration of larger quantities of culture. 
SUMMARY 
(1) Anthrax serum was fractioned by the methods used in the prepara¬ 
tion of diphtheria antitoxin. The anthrax antibodies were associated 
with the pseudoglobulin fraction. 
(2) The globulin preparations contained the antibodies in a concen¬ 
trated form. This was shown in numerous tests on laboratory animals. 
The preparations were likewise potent in tests on larger animals—that 
is, cattle, horses, etc. When administered to human beings (men) 
infected with anthrax, the globulin preparations were found to have 
great therapeutic value. However, no data have yet been obtained 
which permit accurate measurement of the potency of either the serum 
or the globulin obtained therefrom. 
(3) The methods of analysis of serum and similar preparations of 
globulin have been improved by the use of the centrifuge instead of fil¬ 
tration as a means of separating globulin precipitates from their filtrates. 
The precipitates are obtained in compact form with a minimal amount 
of absorbed supernatant fluid. There is no need for reprecipitation. 
(4) The changes in the amounts of the serum proteins in a mule under¬ 
going immunization to anthrax were similar to those usually noted in the 
serum of animals being immunized to diphtheria, tetanus, and rinder¬ 
pest—that is, there was a pronounced rise in the content of total coag- 
ulable protein and total globulin. 
(5) Favorable results follow the use of anthrax serum or globulin 
preparations in the treatment of anthrax in man or animals. The globu¬ 
lin preparation is probably superior to the serum in the treatment of 
the disease in man, since the dose is smaller, and may be safely given 
intravenously, and the danger of anaphylaxis is minimized. 
