296 
FRANK S. BILLINGS. 
enabled our agriculturists to do something to prevent its spread. 
Our investigations (!) have shown that swine-plague is a non-re¬ 
current fever.”— Report , 1883, p. 57. 
The assertions of Law and Salmon that swine-plague is “a 
fever,” show a bad want of a proper education in the principles 
of pathology. u A fever ” as a specific disease is a pathological 
impossibility. The fever is a general phenomenon common to all 
irritative diseases, whether specific or not. Hence, when accom¬ 
panied by fever, in common with every other acute infectious dis¬ 
ease, swine-plague is not “a specific contagious fever,” any more 
than it is a “ non-recurrent fever,” wdiile in the majority of cases 
it is a “ non-recurrent ” disease. 
Detmers, on the contrary, is practically correct in his conclu¬ 
sions, in that by u indirect infection ” he means infection pure 
and simple. 
To the unreflecting veterinarian, or non-professional reader, 
the above may at first appear as an attempt at splitting a hair, 
but it is far from that; to the correct treatment of any disease— 
medicinal or preventive—it is absolutely essential that both pro¬ 
fessional and laymen who may have anything to do with it should 
know what it is. Without this knowledge, any rational preven¬ 
tion of swine-plague will be found impossible. 
A contagious disease is an endogenous disease : that is, one 
which invariably finds its primary origin in a specific element— 
also a micro-organism—which, with equal invariability, finds its 
proto-development within the individual organisms of a given 
species of animal life. 
A contagious disease is communicated directly from one ani¬ 
mal to another of the same or a susceptible species. Syphilis, 
pleuro-pneumonia contagiosa, are examples of contagions diseases 
limited to a single species. On the other hand, while the second 
variety are transmissible to a varied number of susceptible spe¬ 
cies of animal life, still they find their primary development in a 
given species with an equal constancy to the first named. To 
this class belong glanders, rabies, small-pox, foot-and-mouth and 
«■ 
many other strictly contagious diseases. 
The differentiating characteristic between contagious and in- 
