76 
PRINCIPLES OF BACTERIOLOGY 
phage (contained in the filtrates of such material as pus, 
stool, infected fluids) has produced definite improvement 
and recovery in numerous infectious diseases. 
No matter what the nature of the bacteriophage is— 
whether it is, as D’Herelle claims, “a bacterium within 
a bacterium/’ or a ferment produced by intestinal 
mucous membrane, as claimed by Kabeshima, or an 
autolytic ferment produced by bacteria themselves, as 
claimed by Bordet—D’Herelle’s phenomenon is one of 
the greatest bacteriological discoveries of recent years, 
and one which promises to revolutionize our conception 
of immunity, infection and treatment of infectious 
diseases. 
VII. Anaphylaxis 
Anaphylaxis is the opposite of prophylaxis—the lat¬ 
ter is the prevention of infection, while anaphylaxis 
(from Greek ana, meaning against or no, and phylaxis, 
meaning protection) means an abnormal sensitiveness to 
infection. 
By anaphylaxis we mean sensitiveness due, not only 
to bacteria, but to any other proteins; it explains why 
some people are left more susceptible to infectious dis¬ 
ease after one attack than ever before; why some people 
can not eat certain kinds of food, as e. g., shell fish; why 
in some people injection of a serum (not only immune 
serum such as diphtheria, but even a normal horse serum 
which is given to control hemorrhage) produces danger¬ 
ous symptoms of shock, and, at times, even death. 
The main facts about anaphylaxis can be summed up 
as follows: 
1. Any protein—whether bacterial plant or animal— 
can produce anaphylaxis. 
