408 
FRANK S. BILLINGS. 
THE NATURE OF THE AMERICAN SWINE PLAGUE 
IN REGARD TO ITS PREVENTIVE TREATMENT BY VETERINARY 
POLICE AND HYGIENIC METHODS. 
By Frank S. Billings, D.V.M. 
Director of the Experiment Station and Laboratory of the University of Ne¬ 
braska foi' the Study of Contagious and Infectious Animal Diseases. 
[Read before the Massachusetts Veterinary Association by its Secretary, Dr. L. 
H. Howard.] 
(■Continued from page 358) 
SWINE PLAGUE IS AN INFECTIOUS DISEASE. 
Both contagious and infectious diseases have causes other 
than the one specific or exciting cause, the inficiens proper. 
The most striking of these etiological influences, and the one 
in general most difficult to combat, as well as the one which we 
know absolutely nothing about, except its existence, and probably 
never shall know anything more about it, is the racial, or species, 
cause—a causa interna —that peculiar unknown factor which ex¬ 
ists in the greater number of individuals, in certain species of 
animal life, which of itself predisposes such individuals to certain 
diseases to which the individual members of other species have 
no such predisposition. This condition is known as the natural, 
or racial, predisposition. The human race has this natural pre¬ 
disposition to the measles, mumps, scarlet, typhoid, typhus and yel¬ 
low fevers, cholera, syphilis, etc. In fact, unfortunate humanity 
seems to have been especially selected by nature as an example of 
this natural predisposition. Why we don’t know. It certainly is 
not because 
“ In Adam’s fall 
We sin-ned all.” 
No sensible man believes such “ rot ” as that, now-a-days. 
The bovine species has its contagious lung-plague and rinderpest; 
the canine its rabies; the ovine its variola, or pox ; and the por¬ 
cine its swine-plague. Other diseases of this nature, while 
primarily developing in (contagion) or infecting a given species, 
are still susceptible of accidental (not natural) extension to other 
species—glanders, foot-and-mouth disease, small-pox, rabies 
(again), the German “ wild-seuche,” etc. 
