172 BOXE AND BONE MARROW 



D. Eosinopliile marrow cells ; cells of this type possess a broad 

 rim of coarsely granular cytoplasm, the granules of which are 

 strongly acidophile. Their nuclei differ from those of the corre- 

 sponding cells of normal blood, since in the marrow they may 

 possess either a single ovoid nucleus, a polymorphous nucleus, or 

 they may be distinctly multinuclear, in which latter case the nu- 

 cleus consists of two or more discrete ovoid chromatin masses. 





FIG. 164. FROM A SECTION OF BED MARROW OF A HUMAN BONE. 



a, giant cell ; 6, leucocytes ; c, nucleated red blood cells ; d, mitosis in a marrow cell ; 

 e, outline of a fat cell ; /, reticuluni ; g, mitosis in a giant cell, x 680. (After Bohm 

 and von Davidoff.) 



Many of the myelocytes are undoubtedly derived from the circu- 

 lating blood, though most of them arise in the marrow by mitotic 

 division of parent cells of the same type. 



2. Mast Cells. These cells are somewhat larger than the mye- 

 locytes. Their cytoplasm contains a number of coarse basophile 

 granules, and their nucleus is of the polymorphous type. They 

 are undoubtedly formed within the marrow, and probably arise by 

 indirect division of similar cells. 



3. Giant Cells or Myeloplaxes. These cells are of extremely 

 large size (30 to 100ft). They consist of an expansive mass of 

 finely granular cytoplasm, and are either polynuclear or multinu- 



