DISEASES OF BLOOD AND BONE MARROW 97 
presents any distingiusliing features that a specimen in 
poor condition may not exhibit. The monkeys formerly 
dying of tuberculosis had not infrequently pale buccal 
mucosa and skin around the eyes, but upon exam- 
ination of their viscera, blood or marrow the quality of 
their blood could not be called greatly substandard. Slide 
smears of secondary anemia in many specimens would 
occasionally show stippling or a moderate number of 
nucleated cells with anisocytosis and poikilocytosis. 
This is much more frankly exhibited in the Aves, wherein 
displaced karyolytic or pyknotic nuclei are very common. 
Mention has been made of the rifts in the protoplasm, 
seen in Herodiones, and this has been observed in other 
orders. Perhaps the most striking change is the increase 
of young erythrocytes and of thrombocytes in the winged 
creatures. The nucleus of the former reminds one of that 
of the human plasma cell. 
The condition of the bone marrow corresponds with 
fair accuracy to that which one is accustomed to see in 
the human being. Certainly this holds good for the 
mammals, while among the birds, the few observations 
upon which we feel like relying indicate a nodular 
erythropoiesis of rather striking character. In the areas 
of reddening as seen grossly there will be found under 
the microscope an orderly arrangement of large red cells 
with loose chromatic nuclei about a very much larger cell 
of the same type, apparently the primary erythroblast. 
Outside of this group, red cells such as appear in the 
circulating fluid, are rather irregularly distributed in a 
marginal zone. I have seen small areas like this in 
apparently normal marrow, but the central grouping 
was not so large as in the anemic cases ; it thus appears 
that we probably have the anatomy of erythropoiesis. 
The deposition of pigment in the birds is in much 
coarser granules than among the mammals, in the former 
case large masses sometimes obscuring several liver cells 
