266 DISEASES OF DOMESTICATED BIRDS 
closely related to cells of the lymphoid series. The blood found in 
the vessels of various organs and tissues contains large numbers of 
these cells, so that the proportion of white cells in the circulating 
blood is very great. In addition to the nodules of tumor tissue 
found in the liver and kidneys, these organs are to a large extent 
infiltrated with tumor cells. 
A ease of lymphoma of the neck with metastasis to the lungs and 
the liver without lymphatic leukemia is described by the same 
writers. The cervical tumor appears as an oval flattened mass with 
an elevated rounded edge and a thick central crust. It measures 5 
by 6 cm. across and 2 em. in thickness. On section it is found to be 
composed of rounded cells which vary considerably as to size, and 
which contain rounded, somewhat irregular nuclei. The liver is 
greatly enlarged. The right lobe presents a rounded nodule, 1 cm. 
in diameter consisting of tissue of similar appearance to that of the 
primary tumor. The entire liver is infiltrated with this tissue 
which appears to augment the size of the lobules and in places grows 
diffusely in areas 2 to 5 mm. in diameter. The tumor involves both 
lungs, and only a small portion of one lung contains air. Near the 
roots of the lungs are two rounded nodules of tumor tissue. The 
tumor consists of cells with little supporting tissue. The latter 
consists for the most part of a delicate reticulum of connective tissue 
which apparently does not develop to any considerable extent within 
the tumor, but represents preéxisting tissue into which the tumor 
has grown. There are also a few coarser bands of fibrous tissue. 
The tumor is rather vascular throughout, and the connective tissue 
reticulum is more distinct around the vessels than elsewhere. The 
tumor cells vary in size. Many are no larger than the lymphocytes 
of the circulation but some are equal in size to large connective tissue 
cells. They are apparently not concerned in the formation of in- 
tercellular fibrils. 
Another case reported presented a primary tumor of the nature 
of a lymphoma, situated on the neck, with secondary nodules on the 
sternum, in the lung and in the liver. The sternum and adjacent 
muscles are infiltrated with the tumor, but the tumor occurs as dis- 
crete nodules in the lung and liver. The spleen is not involved and 
the blood appears normal. 
Warthin observed several cases of leukemic lymphocytoma in 
fowls in which there were observed tumor-like nodules and infiltra- 
tion of lymphoid cells in all the organs, particularly in the liver, 
spleen, kidneys, bone marrow, and hemolymph nodes. He observes 
