296 H. E. JORDAN 
However, when we consider the granulocyte inclusions, the 
case seems quite different. In the first place, such cells do not 
occur in the yolk-sac giant-cells. Here the cells are quite widely 
scattered in the blood spaces, and not closely crowded as in the 
bone-marrow. Furthermore, these granulocytes may occur in 
practically any type of older giant-cell in red bone-marrow, but 
most abundantly in those cells whose nuclear condition indicates 
degenerative changes in these cells; witness the figures of Denys. 
If the presence of the eosinophilic polymorphs signified giant- 
cell phagocytic activity, then one would expect all types of mar- 
row cells to be ingested in approximately equal numbers. But 
the polymorphs with fine eosinophilic granules very greatly pre- 
ponderate. When one considers the fact that the polymorphs 
of the rabbit with fine eosinophilic granules (special granulo- 
cytes) are the representatives of the neutrophilic polymorphs of 
most mammals and that the latter are the predominant phago- 
cytes, Heidenhain’s suggestion that these granulocytes have in- 
vaded the giant-cell appears very plausible. This conclusion is 
in agreement with the fact of their greater abundance in ob- 
viously degenerating and disintegrating cells. 
The observations of Denys as illustrated in his figures 16 to 23 
are absolutely unique. No one else, as far as I have been able to 
learn, has described anything closely comparable in degree with 
conditions he describes for his sections of rabbit’s red bone-mar- 
row. He does say that great variations occur in regard to these 
conditions in different individuals, but he does not specify any 
peculiar circumstance about the individual from which this 
specimen of marrow was derived. In my study of preparations 
of at least a score of different individuals of rabbit and guinea- 
pig I have never seen anything like the condition illustrated by 
Denys in, for example, his figures 22 and 23. Dickson would 
explain these conditions as phagocytosis; Heidenhain as the re- 
sult of invasion. However correctly interpreted, the condition 
of this degree must be extremely rare. Besides the arguments 
above given against an interpretation in terms of phagocytosis 
on the part of the giant-cells, may be mentioned this additional 
and apparently conclusive contravening fact as applied to the 
