138 CANINE DISTEMPER 
MORTALITY. 
True to the characteristic variability which marks this 
disease from every aspect, the death-rate fluctuates, 
being greater in some seasons or in some outbreaks than 
in others, and less in country districts than in large cities. 
The average mortality may be assessed at 25 per cent. 
Miiller and Glass estimate it as between 60 and 70 
percent. in big cities, and at 20 to 30 percent. elsewhere ; 
Youatt computes it at 33 per cent.; Millais, 60 to 90 
per cent., and of the highly-bred, 90 per cent.; Gray, 
25 per cent. ; Ferry, 90 per cent. among pure-bred dogs 
in New York, and 60 to 80 per cent. among ordinary 
street mongrels; Friedberger and Frohner, 50 to 60 
per cent. . 
These discrepancies arise doubtless from the fact that 
some of these authorities have based their figures upon 
the results of certain epizodtic outbreaks of a virulent 
type, whilst others have probably taken an average spread 
over many years of practice, thus embracing sporadic 
cases in addition to those of epizodtic origin. I do not 
think any general practitioner to-day will estimate the 
death-rate higher than approximately 25 per cent. 
The age and breed of animals affected exert a strong 
influence on mortality, very young puppies or aged 
adults being far more apt to die than animals between 
the ages of four and twelve months and up to five or six 
years. Similarly, highly-bred animals, and those exotic 
to a country, will perish in much greater proportion than 
the common mongrel or indigenous breeds. Among the 
latter again we find some breeds are more highly resistant 
than others, such as fox-terriers, bull-terriers, Irish 
terriers, Airedales, spaniels, setters, etc., in which prob- 
ably only about 17 per cent. of cases prove fatal. Collie 
dogs, however, appear to be peculiarly susceptible to 
