ETIOLOGY 23 
might have no connection with typical distemper, as 
follows : . 
“Broncho-pneumonia is not the only pathological 
lesion induced by the experimental injection of B. broncht- 
septicus. J have seen all stages of the disease produced, 
from a slight cough and diarrhoea to a case of distemper 
with all the sequela, due to secondary infections, and 
even a general septicemia, where a pure culture of 
B. bronchisepticus was isolated from the heart's blood. 
Torrey, according to his publications, has had practi- 
cally the same experience. He used the nasal route of 
injection, while I used the tracheal.” 
Analogy to Swine Fever.—The whole case seems to be 
analogous to that of swine fever, the etiology of which 
is universally declared to be a filterable virus, in spite of 
the fact that in every pig dead of the disease the Baczllus 
suipestifer can be demonstrated in its lesions. Although 
regarded like the B. bronchisepticus as only a secondary 
invader, it is nevertheless a fact that this organism, if 
fed to healthy pigs, will produce a typical attack of 
swine fever, even as B. bronchisepticus will set up typical 
distemper, and in neither case is the presence of the 
virus essential. It is equally true that whereas each 
virus when inoculated into its respective animal will 
produce its particular disease, the B. suipestifer can be 
unfailingly recovered from lesions in the pig, and the 
B. bronchisepticus from those in the dog, thus apparently 
proving that the organisms are constantly and signifi- 
cantly associated with these maladies. Swine fever, as 
experimentally produced by feeding the culture of B. 
suipestifer, is, however, not zaturally contagious to other 
pigs, and confers no immunity, and we have yet to be 
assured that the distemper provoked in one dog by 
artificial inoculation of Ferry’s bacillus is infective to 
other dogs by cohabitation, and after a period of illness 
leaves them permanently protected against future attacks 
