GIANT-CELLS OF BONE-MARROW 291 
cellular origin of erythrocytes from giant-cells. Van der Stricht 
(17) ascribes to-the giant-cells of marrow the function of ingest- 
ing the nuclei of enucleating erythrocytes. 
According to Dickson (5), the giant-cell with polymorphous 
nucleus becomes multinucleated by an exceedingly complicated 
series of nuclear alterations which he describes as ‘incomplete 
division by mitosis.’ He interprets the phenomena described 
by Arnold as ‘indirect fragmentation,’ as the pyknotic changes 
characteristic of degenerating giant-cells. He regards all cellu- 
lar inclusions as the result of phagocytosis, and denies any hemo- 
poietic function on the part of the medullary giant cells. 
Van Bambeke and Van der Stricht? describe the origin of the 
polymorphous nucleus of the so-called ‘megakaryocytes’ of red 
bone-marrow as the result of fusion of a large number of small 
daughter-nuclei derived from repeated multipolar mitoses. Such 
polymorphokaryocytes may later, according to their view, divide 
into similar daughter-cells by a long-retarded cytoplasmic divi- 
sion. The polykaryoctes would therefore represent a transient 
phase immediately following a multipolar mitosis. 
Denys (4) claims that the giant-cells divide both by mitosis 
and by amitosis. The latter method is involved in the hemo- 
eytogenic activity of these cells, by which both leucocytes and 
erythrocytes are said to be produced. From the viewpoint of 
our present interest, the article by Denys is the most important 
of the afore-mentioned group and calls for detailed consideration. 
Denys derives the polymorphokaryocyte (figs. 3, 7, and 8)* from 
the megakaryocyte (figs. 1 and 2); the former becomes a poly- 
karyocyte (figs. 4, 16, and 17) by completion of the constrictions 
in the lobulated nucleus to form discrete smaller nuclei. About 
these separated nuclear ‘buds’ the cytoplasm is said to differen- 
tiate in a manner to produce intracellular blood-cells, both leuco- 
cytes and erythrocytes (figs. 8 and 9). Of the several hundred 
2 The original paper was not accessible to me. I quote here from a reference 
to this work in a paper by Van der Stricht and Todd. (The Johns Hopkins Hos- 
pital Reports, vol. 19, p. 34.) 
3 Unless otherwise specified, all references to figures are to those accompany- 
ing this article. These figures include types of all varieties of giant-cells illus- 
trated in the articles cited in the text. 
