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quite a wide range of temperature and it is more than probable 
that some agent other than the body temperature of the subjects 
mentioned has something to do in causing this natural im¬ 
munity. There are, however, certain pathogenic bacteria to 
which the above theory may hold good, e. g., the tubercle 
bacilli, which require a temperature of 37 degrees C. or more 
for their multiplication. 
The reaction of the body fluids, according to the experi¬ 
ments of Behring, seems to have a decided influence in produc¬ 
ing the decided immunity of the white rat to anthrax. The 
blood of these animals is decidedly alkaline, to which is attributed 
the remarkable resistance of these animals to virulent cultures 
of the bacillus of anthrax. When so fed, however, as to render 
their blood acid they readily yield to the disease. It has also 
been shown by Behring, Nuttall and others that recently drawn 
blood of naturally immune animals has a decided germicidal 
effect on certain pathogenic bacteria, while upon others it has 
no such effect. Buchner has demonstrated that this power be¬ 
longs to the fluid part of the blood and not to the cellular 
elements. This power is said to be destroyed by heat, and lost 
when the blood has been kept for a considerable length of time, 
but is not affected by cold. It is also claimed that this power 
of the blood is very decided in its action, but limited to a given 
number of bacteria, and that when this number is exceeded that 
rapid development of the germ takes place in the blood serum, 
but becomes very much attenuated. 
Hankins has isolated from the spleen and blood of rats a 
substance which has decided germicidal properties, and which 
he terms globulin . While keeping in view the alkaline theory, 
he attributes the power of rats’ blood to destroy the anthrax 
bacillus largely to this globulin. 
Kitasoto and others have published interesting results of 
their experiments in which they made a bouillon from the 
thymus gland of a calf. It was found that the tetanus bacillus 
when cultivated in this fluid did not form spores and had but 
little virulence. Small animals inoculated with small quantities 
