PLASMA CELLS OF HOFBAUER 345 
cocytes and the disintegrated pigmented detritus. The phago- 
cytic nature of these cells is especially noticeable in the specimens 
of young chorionic vesicles with nucleated reds, stained with 
iron hematoxylin, for in these the leucocytes are often seen 
filled with a mass of nuclei only. 
Similar appearances can also be seen occasionally in the decidua 
from cases of endometritis, as well as in portions of the decidua 
in which the glands have undergone considerable maceration and 
degeneration. In the former the polymorphonuclear leucocyte is 
the misleading form, while in the latter the degenerating, cast-off 
glandular epithelial cells simulate Hofbauer cells in almost every 
morphological detail. I have also seen similar specimens of degen- 
erated polymorphonuclear leucocytes in ill-preserved hemorrhagic 
lymph nodes, especially from cases of septicemia, and, until the true 
nature of such degenerate leucocytes became evident, it was very 
puzzling to see why the Hofbauer cell, which never was found to 
contain evidences of phagocytosis when lying in the stroma of 
the villus, should become phagocytic when contained in a de- 
generated amniotic or chorionic membrane or when lying in 
a hemorrhagic area. Undoubted instances of phagocytic Hof- 
bauer cells were never seen, although certain misleading forms 
other than those already mentioned were encountered also in 
pregnant tubes and in an ovarian pregnancy. Among these 
misleading forms were specimens of binucleate cells in which 
one nucleus had undergone almost complete chromatolysis, 
leaving only a nuclear membrane. These nuclear remnants 
or so-called nuclear shadows, can easily simulate a phagocy- 
tosed erythrocyte. The same is true of small areas of cyto- 
plasm which stain but faintly, and hence look more translu- 
cent, and particularly of vacuoles themselves. 
Essick (15) found what he regarded as morphologically sim- 
ilar cells in transitory cavities in the corpus striatum, and 
believed them be macrophages. Consequently, he concluded 
that Hofbauer cells also are phagocytic and regarded them as 
having an endothelial origin. I have not been able to find any 
evidence for the latter origin, however, for in specimens in which 
the capillaries are plugged with degenerate endothelial cells 
