262 DISEASES OF DOMESTICATED BIRDS 
Ehrenreich collected data on the frequency of the occurrence of 
tumors in fowls. Arrangement was made with a hotel to have sent 
to him the organs of all birds noticed to contain tumors. From 
nearly 2000 mature hens he obtained 7 malignant tumors of which 
5 were surely carcinomata. Doubtless the hotel employees over- 
looked many small tumors. It should be noted that the birds ex- 
amined were in apparent health and the discovery of .carcinomata 
was purely accidental. Under more favorable conditions, the per- 
centage of carcinomata would have been higher. Among 3000 
pullets under a year old, no carcinomata were found, which confirms 
the belief that carcinoma is associated not with youth, but with 
maturity. 
CARCINOMA 
One carcinoma described by Ehrenreich was about the size of a 
hazel nut and had developed between the gizzard and the spleen. It 
was in contact with the upper end of the small intestine which 
showed stenosis at that point. The consistency was soft, the surface 
uneven and covered with shiny serosa. The color was gray and on 
section showed a few yellow points. Microscopic examination 
showed the tumor to be an adeno-carcinoma. 
Two more highly differentiated adeno-carcinomata were obtained 
from the ovary. They were about the size of a small apple or a 
man’s fist, were of solid consistency, had rough surfaces and were of 
a reddish gray color. In both cases a seeding of small metastatic 
tumors on the peritoneum had occurred. 
Ehrenreich and Michaelis described three malignant tumors of 
the hen, of which two were adeno-carcinomata and one was a sar- 
coma-like tumor. 
SQUAMOUS CELL CARCINOMA 
Pick described a squamous cell carcinoma located beneath the 
floor of the mouth of a hen and which caused a marked deforma- 
tion of the region. The subject was a hen about seven years old. 
The tumor was observed at New Year’s as a small lump and by 
September had grown to a mass measuring 4 by 3 by 3 cm. when the 
bird was killed. The tumor was located in the rear half of the floor 
of the oral cavity and bulged out on each side. It extended down- 
wards to the sparsely feathered area between the wattles. The sur- 
face was smooth except for a small ulcerated spot near the beak. 
On section it was observed that the tumor was necrotic near the 
