610 DISEASE IN WILD MAMMALS AND BIRDS 
drooping head ; the stools were little if any altered as far 
as could be determined among so many in the enclosure. 
At death the birds were in good condition, feathers fairly 
smooth, skin clear, body plump and fat in good amount — 
not abundant, nor were the animals emaciated. The 
principal lesions were enteritis, degenerative, necroses 
and abscesses in the liver, congestion of all the viscera 
and plastic peritonitis in a few. A small number showed 
congestion of the Imigs and two had patches of pneu- 
monia. Many but not all of the birds had Heterakis in the 
ceca. The process seemed to start as a focal necrotizing 
lesion in the mucosa or submucosa of the ileum just above 
the ceca and colon ; many had lesions in the ceca and as 
far down in the colon as the cloacal dilatation. Among the 
animals dying late in the epidemic several showed lesions 
involving the whole small intestine, a few indeed with 
greater involvement of the duodenum than of the 
lower parts. 
''Judging from the gross and microscopical appear- 
ances it seems that the virus causes at first a cellular infil- 
trate in the mucosa or submucosa upon which necrosis 
shortly supervenes. The overlying mucosa soon degen- 
erates, and the surface is covered with an indefinite 
slough. In other cases, especially early in the epidemic, 
the process extended outward and appeared as muscular 
or subperitoneal necrotic areas before the mucosa was 
much involved. At all events necrosis was an early 
change in every case. The blood vessels were usually 
thrombotic. In the cases that spread toward the peri- 
toneum a plastic peritonitis of varying severity was 
present. The focal liver lesions were not present in every 
case. They took the form of focal necroses or abscesses. 
Some fatty or parenchjnnatous degeneration was always 
present. The liver lesions probably started as inflamma- 
tions of the veins from which necrotizing or infiltrative 
lesions spread. The splenic lesions were those of 
l>Tnphoid hyperplasia, only distinctive in the enormous 
