GIANT-CELLS OF BONE-MARROW 293 
and 4. But these two cells (figs. 1 and 2) and many others have 
approximately as simple a nucleus as represented in these illus- 
trations. The cell of figure 2 can be traced through small grada- 
tions to one like that of figure 3, a polymorphokaryocyte. The 
nucleus has become more complex and lobulated. A central 
cytoplasmic area (‘endoplasm’ of Heidenhain) contains a con- 
spicuous group of centrosomes. There is, however, no indica- 
tion of archoplasmic fibers. 
By constrictions at the levels between adjacent lobules, the 
nucleus of the polymorphokaryocyte becomes divided into smaller 
nuclei, producing thus a polykaryocyte (fig. 4). This cell also 
contains a conspicuous pluricorpuscular centrosome in the ‘endo- 
plasm.’ Appearances of discrete nuclei, like that of figure 4, 
could conceivably result from tangential sections through poly- 
morph nuclei like that of figure 3, but in this particular case 
again, and in many others, it could be proved by study of serial 
sections that the giant-cell actually contains in certain instances 
several or many discrete nuclei. 
In figure 9 is illustrated a giant-cell in which three nuclear 
buds have separated from the main polymorphous nuclear mass. 
Two of the nuclear buds (a and c) have the features of nuclei of 
the marrow erythroblasts; and about nuclear mass c¢ a layer of 
cytoplasm has separated from the giant-cell ‘exoplasm,’ thus 
giving origin to an erythroblast which now appears to lie in a 
vacuole. Figure 8 illustrates in simplest condition the amitotic 
mode of intracellular hemocytogenesis described by Denys, as 
above outlined. ‘This cell contains a polymorphous nucleus with 
scattered centrosomes in the ‘endoplasm.’ At the right periph- 
ery lies a polymorphonucleated eosinophilic granulocyte. In my 
preparations any of the cells illustrated in figures 3, 4, 7, 8, 9, 
10, 11, 16, and 20 may contain one or several eosinophilic gran- 
ulocytes. But only multinucleated cells like those of figures 4 
and 9 contain erythroblasts. 
