TUMORS IN FOWLS 265 
FEATHER CYSTS 
Koch observes that feather cysts (cystomata pennifera) occur in 
hens and geese, which are analogous to the dermoid cysts of mam- 
mals. 
LYMPHOMA 
Tyzzer and Ordway observe that lymphomata occur both with and 
without lymphatic leukemia. They regard the latter condition as 
due to the presence in the circulating blood of tumor cells having 
the characteristics of the cells of the lymphoid series. The only dis- 
tinction made by them between a leukemic lymphoma and lymphoma 
with lymphatic leukemia is that in the former the tumor is ex- 
travascular while in the latter the tumor is intravascular. Tumors 
observed by them occurred as definite primary growth either with or 
without secondary nodules or were so disseminated that the site of 
origin could not be determined. Some of the tumors have a more 
or less alveolar structure while others grow diffusely by infiltrating 
normal structures. Examples are given of a few cases observed by 
Tyzzer and Ordway. 
Lymphoma associated with lymphatic leukemia. Lympho- 
matous tumors are disseminated throughout the liver, the kidneys 
and the peritoneum; lymphatic leukemia. The subject is a hen at 
least one and possibly two years of age. The liver is greatly en- 
larged and presents many distinct rounded nodules of pale pink 
color distributed through its substance. Many of these nodules are 
apparent in the surface of the liver. Some present slightly de- 
pressed central areas, and elongated rounded borders. The largest 
measures 3 cm. across. The spleen is several times its normal size 
and is rather soft. The cervical lymph glands are enlarged. The 
kidneys are enlarged and studded with rounded pink nodules, some of 
which are 4 mm. in diameter. Distributed over various portions of 
the peritoneal surface are elevated plaques of tissue from which 
small blood vessels radiate into the surrounding normal tissue. 
The tissue of this case being poorly preserved it is impossible to 
determine the finer histological features of the cells. It is apparent, 
however, that the nodules in the liver, the kidneys, and the peri- 
toneum are composed of cells somewhat larger than the lymphoid 
cells of the circulating blood of the fowl and possess a more or less 
spherical, eccentrically situated nucleus. They correspond quite 
closely in their morphology to the plasma cell, and are evidently 
