Diseases of the Respiratory Organs. 33 
changing it and also to the general sanitary condition of 
the place. The disease broke out, too, during a spell of very 
severe weather, when the food left in the pans froze quickly. 
The course of the epidemic was short, lasting between six 
and seven weeks, a sufficient time, however, to destroy 
almost all.the pups in the kennels. 
“The mode of invasion in parasitic disease of the bron- 
chial tubes has been, and still is,a matter of much dispute, 
some observers maintaining that ‘the ova and young para- 
sites taken up with the food in the first place gain access 
from the alimentary canal to the circulation ;’ others hold 
the view that they pass directly from the mouth to the 
trachea, or that the ova are inhaled by the breath. The 
former view is the one most generally entertained, and it 
is urged in its favour that the presence of the worms has 
been determined in the cavities of the heart and in the 
blood-vessels, as well as in the intestines. Now, in the 
epidemic under consideration, I think this view does not 
meet thecase. Supposing the young embryos to have been 
ingested and to have gained access to the branches of the 
portal vein, they would then be carried to the right side of 
the heart, and from thence to the lungs, by the pulmonary 
artery, the capillaries of which ramify in the lung-substance 
alone, a situation in which the parasites did not occur. To 
get to the bronchial mucous membrane they must be re- 
turned by the pulmonary veins to the left side of the heart, 
enter the aorta, and pass out by the small bronchial arteries 
which supply thetubes—an exceeding roundabout and some- 
what improbable route. It is to be remembered that young 
strongyles have been found capable, like many other nema- 
toid worms, of reviving on the application of moisture after 
a desiccation of a month or more, and even after immersion 
in spirits of wine and solutions of corrosive sublimate and 
alum (Williams), so that their chance of survival under 
adverse circumstances is unusually good. It seems 
quite as reasonable to suppose that the dried em- 
