724 
ED. NOCARD. 
Any horseman can recognize a well developed spavin or ring¬ 
bone, but it often taxes the judgment of the most experienced 
practitioner to recognize incipient pathological processes that 
render a horse unsound. W. H. R. 
ORIGINAL ARTICLES. 
PROPHYLAXY OF INFECTIOUS DISEASES OF DOMES¬ 
TIC ANIMALS. 
By Prod. Ed. Nocard,* France. 
(Concluded from page 660.) 
( 2 ) PROPHYLAXY WITH INOCULATION OF PURE OR WEAKENED 
VIRUSES. 
We have arrived at the second group of means to realize 
prophylaxy. 
Many infectious diseases do not return a second time ; once 
removed from a first attack it is very likely that it will not re¬ 
turn a second time. One has become refractory to that disease. 
It is the well known case of small-pox. It is the type among 
diseases that do not return ; it is so also in cases of pleuro-pneu- 
monia, of variola in sheep, rinderpest, anthracoid diseases, rou- 
get of swine, cholera of fowls, rabies, Texas fever, horse sick¬ 
ness, etc. It is very rare in many of these diseases to observe a 
return of the disease, because most of the affected animals die. 
Rabies is always fatal ; recovery from rinderpest, anthrax, 
chicken cholera, rouget, horse sickness, is rare and very excep¬ 
tional. But those who have the good fortune to recover are 
then protected from a new attack ; they sustain without trouble 
the inoculation of a virus which kills all fresh animals. 
These facts, known from time immemorial, have suggested 
the idea of producing diseases artificially, to avoid the fatal 
affection. This course presents several advantages : the disease 
* Extract from LI Ingenieur Agricole de Gembloux. Translated by A. Liautard. 
