Leukemia of the Fowl. 9 
second, the blood is characterized by a predominance of small and 
large lymphocytes (90 per cent of the total number) occurring in 
association with a pronounced lymphomatosis (numerous infiltrations 
with lymphoid cells) of the organs. Of interest is the fact that a 
myeloid type may occur in one generation and a lymphatic in the 
next, or that both types may occur in the same generation. The 
occurrence of both types in the same stock suggests very strongly 
that both forms of leukemia in man are due to one and the same 
infection. 
II. Stupres on THE Norma Fowt. 
With the hope of making the findings in the leukemic animals more 
clear, the following brief data of the normal fowl] are presented. These 
are limited to those portions of the body which are involved in 
leukemia. They are compiled from a large number of chickens. 
EXTERNAL APPEARANCE. 
Healthy, young, adult Plymouth Rock hen. Comb, featherless 
area about eyes, and wattles bright red. Conjunctive and buccal 
mucous membrane pink. Skin of body white with a faint yellow 
tint. Well nourished, sides of sternum covered with a thick pad of 
tissue, ribs not palpable. Average rectal temperature, 42 ° C. 
BLOOD. 
The blood for counting and smears was obtained from the vein under 
the wing, which always appears to be well filled. From a small needle 
puncture the blood flows under pressure, is thick, dark red and clots 
quickly. 
Blood-count.—The nuclei-containing red blood cells of the fowl 
make it practically impossible to count the white blood cells by the 
usual direct method. After laking the former, one cannot differ- 
entiate between the nuclei of the two types of cells. It was there- 
fore necessary to resort to the indirect method, i. ¢., to determine the 
proportion of white to red cells from a stained smear, count the total 
number of cells, both whites and reds, by the direct method, and then 
calculate the total number of each present. 
The red blood cells vary somewhat: lowest limit, 2,500,000 ; highest, 
4,500,000 ; average, 3,000,000-4,000,000 per c.mm. White blood cells: 
