28 CANINE DISTEMPER 
is yet frequently generated, and in this bears an analogy 
to mange, and to farcy and glanders in the horse.” Such 
a theory as “spontaneous generation,” however, is 
quite exploded, for all the maladies mentioned can only 
be created by their respective specific parasites or 
organisms. , 
Latent Infection.—There is, of course, such a con- 
tingency as latent infection, in which an animal appears 
to harbour the contagium and disseminate it to others, 
without itself showing any manifestations of disease 
whatever. Such an animal is said to be a “ carrier,” and 
he may remain so for at least three months, and possibly 
even longer, after recovering from distemper, especially 
if there had been middle ear or frontal sinus com- 
plications. 
