20. CANINE DISTEMPER 
The results of the work proved conclusively—accord- | 
ing to all rules as laid down by the several authorities 
on filterable viruses—that the B. bronchisepticus is a 
filterable organism. The work also corroborated the 
results of previous investigators with regard to the fact 
that the less pressure used, the more easily will some 
organisms pass through the filters. Since 1905, when 
Carré claimed that he had produced typical symptoms of 
distemper in susceptible dogs from the filtered discharges 
of diseased dogs, the majority of writers (as already 
stated) have classified the etiology of canine distemper 
as a filterable, invisible, or ultramicroscopic virus, and it 
is so described in many textbooks. 
The work of Ferry, M‘Gowan, Torrey, and Wherry 
with the B. bronchisepticus tended to refute the state- 
ments of Carré, especially as their work was carried 
on at the same time and quite independently, thus lend- 
ing great weight to their claims. The work of Carré, 
however, is not entirely disregarded, many still accepting 
his position; but the results of the filtration experiments 
with the B. bronchisepticus might appear to put an 
entirely new light on the subject, as it could be argued 
that if the B. bronchisepticus is the cause of canine dis- 
temper, then the experiments corroborate the work 
of Carré. If the work of Carré is correct, and if the 
causative agent of distemper is a filterable virus, then 
the experiments point very conclusively to B. bronchi- 
seplicus as the cause, and confirm the findings of the 
above-named investigators. 
There is, however, a serious objection to this other- 
wise lucid explanation—namely, that the filtrates of 
Carré were said to contain no discoverable or cultivable 
organism. Thus, granting that Ferry’s bacillus could pass 
through the filter, it should still be possible to cultivate 
the organism by inoculating an artificial medium with 
