10 CANINE DISTEMPER 
from a dog sick with it. I have always regarded it as 
just as safe to allow a healthy cat freedom to wander in 
the proximity of distempered dogs, as it would be fatal 
to permit a healthy young dog to follow in its footsteps. 
Other British observers appear to concur in this view, 
the contention being that cats are not naturally prone to 
contract the disease from dogs, ee they might do so 
under artificial conditions. 
Herbivorous animals, such as the or ox, sheep, and 
goat, are immune; as are also pigs and birds. 
Influence of Age and Breed on Susceptibility.—The 
breed and age of a dog certainly appear to exert an 
influence on its susceptibility to attack, and whilst 
distemper may manifest itself at any period of a dog’s 
life (even as may measles in the human subject), yet 
mature or aged dogs possess a far greater immunity 
than do the younger ones. This, however, may be 
accounted for by the fact that few dogs—if any—ever 
reach middle life without having already fallen a prey 
to the disease, and they have acquired therefrom such a 
degree of immunity that subsequent attacks are averted, 
or at least assume a milder type. Professor Williams, 
in his “ Principles and Practice of Veterinary Medicine,” 
remarks: “It affects the system only once.” But contrary 
to this and the popular view, the protection conferred by 
the original attack is not necessarily of a reliable and 
enduring character, and quite 6 per cent. of those of my 
patients which I have been able to trace have fallen 
victims to a subsequent attack. 
In rare instances, two and even three attacks have been 
observed in the same dog, and death has been known to 
supervene on the second or third illness: In buying a 
dog, the full assurance that it is over distemper is there- 
fore no guarantee whatever that the malady will not 
appear again, and there is an abundant accumulation of 
