THE RESPIRATORY SYSTEM 153 
or lobe. It seems that this pseudolobar appearance 
occurs definitely more often in ungulates than in the 
other orders. 
Marsupialia offer two rather easily grouped classes 
of bronchopneumonia — one associated with enteritis and 
one secondary to ' ' Kangaroo disease ' ' of the jaw ; they 
differ in microscopy correspondingly. The simple bron- 
chitic and peribronchitic infiltrate and superficial exudate 
occurring with enteritis or with a general infection is 
relatively diffuse, giving in some instances the impression 
of an interstitial process and showing notably swollen 
septa; there may be fibrin but this is exceptional and 
scanty. When mycosis of the jaw has been the origin or 
occasion of the infection the picture is that of frank aspi- 
ration pneumonia, therefore more like a septic infarct. 
However the amount of fibrin is sometimes very great and 
whole alveoli will be filled with it, perhaps accompanied 
by red cells, polynuclears and epithelia. Epithelial cells 
however play a small part in the minute anatomy. Hemor- 
rhage and edema are prominent but true abscess forma- 
tion and gangrene are not. Possibly the animals die too 
soon for the latter to develop. 
Pneumonia in Aves aside from that due to moulds is 
apparently much less common than among the Mammalia, 
one order onl}^, the Passeres, showing an incidence com- 
parable to the important orders of the latter class. The 
other orders, and this applies particularly to those of 
which we have an adequate number, are quite insus- 
ceptible to simple pneumonia, none of them showing over 
two per cent. There are listed for Aves three instances 
of lobar fibrinous pneumonia. These cases can be 
described together since in all the findings were about the 
same. A whole lung or goodly portion thereof was uni- 
formly involved in a red or gray consolidation of rather 
fine granular character which on section study seemed to 
be made up of the same lesion all over, with fibrin a promi- 
nent part of the exudate. The coagula were largely 
11 
