THE RESPIRATORY SYSTEM 159 
carries them into the right lung because of the larger 
and more directly vertical bronchus to that side. Emboli 
go as a rule also to the right lung more than to the left 
because of the greater size of the pulmonary artery and 
more direct blood current to that side. In these animals 
right side lesions are more numerous but the left lower 
lobe is the principal segment of the lung to be affected. 
The cases are too few and the anatomy too variable to 
permit any deductions. There is in the affected animals 
no uniform anatomical peculiarity which would explain 
the predominance of the right lung as a whole or the left 
lower lobe as a unit. 
Pneumonokoniosis. 
Pneumonokoniosis, because of its importance in indus- 
trial diseases, has been subjected during recent years to 
considerable intensive study in human medicine, from 
which activity some interesting and useful information 
has been obtained as to its genesis and effect upon the 
function of the lung. This condition is of course a purely 
environmental one, the degree and particular kind of 
'' dusting " being dependent upon the duration and 
nature of exposure of the particular individual. This 
Garden is situated beside an active railroad trunk line so 
that the opportunity for coal dust inhalation is con- 
tinuous. The degree of anthracotic pigmentation of the 
lungs and related serous membranes is really negligible 
and with one questionable exception, we have not seen 
fibrosis due to this cause in any animal. The one excep- 
tion, an amazon presented and living in the Garden but 
three months, at necropsy showed an interstitial chronic 
bronchitis and pneumonitis stretching out from the hilum, 
all of the affected area being deeply pigmented. The 
picture was comparable to what might be expected from 
a second degree anthracotic fibrosis of Landis and Pan- 
coast. Many specimens come to autopsy with some grade 
