Leukemia of the Fowl. 23 
polychromatophilia, mostly associated with a swelling of the nucleus 
and separation of its chromatin (0). 
2. Normoblast (¢): Round, diameter less than length of normal 
normocyte. Nucleus round, of same color or slightly purple, but larger 
and with more scattered chromatin than nucleus of normal normocyte. 
Cytoplasm greenish-blue and glassy. Frequently with clear zone about 
nucleus. 
3. Megaloblast (d): Same, except diameter equal to or greater than 
length of normal normocyte. 
4, Mitotic Cells (e): All stages, from monaster to complete division 
of nucleus. (a) Round or elliptical, diameter about length of normal 
normocyte. Dense, deep blue chromosomes, massed in center of cell. 
Cytoplasm greenish-blue and glassy. (b) Same, with two masses of 
chromosomes in opposite extremes of cell. (c) Same (at times with a 
slight constriction in the middle of the cell) with irregular, dense, deep 
blue or slightly purple chromatin masses in place of individual chromo- 
somes. (d) Same, with two nuclei, similar in appearance to those of 
normoblast. (e) Same as normal normocyte with two nuclei, similar in 
appearance to those of normoblast, but only slightly larger than nucleus 
of normal normocyte. (a), (b), (c) and (d) may show polychroma- 
tophilic cytoplasm. 
Blood Platelets (f). 
1. Same as normal, except that cell and nucleus are both larger. 
2. Larger than normal with two nuclei. 
Leucocytes. 
1. Polymorphonuclear leucocyte with eosinophilic rods (g): Same 
as in normal blood, at times possibly a little smaller. 
2. Polymorphonuclear leucocyte with eosinophilic granules (h): 
Same as in normal blood, at times possibly a little smaller. 
3. Lymphocyte (7) : Same as in normal blood. 
4. Large mononuclear cell: (a) As described in normal blood, with 
a little less cytoplasm. (b) Same size to one half times larger than (a), 
with both nucleus and cytoplasm paler (j). (a) and (b) cannot be 
separated absolutely. Every gradation. (c) Mitoses (k): All stages, 
from monaster to complete separation of nucleus. (a’) Elliptical, 
diameter about one and a half length of normal normocyte. Dense, 
purple chromosomes centrally massed. Cytoplasm pale bluish-gray, 
