332 ARTHUR WILLIAM MEYER 
Clivio (03), Stoffel (05),! Vecchi (’06), and Pazzi (’04). In- 
deed, many other names could be added, for surely any one of 
the many who studied even a small series of chorionic vesicles 
must have seen some of them in some villi, especially in unrec- 
ognized cases of hydatiform degeneration, but since they have 
been referred to as Hofbauer cells, it is his description that es- 
pecially interests us. In describing the chorionic villi, Hof- 
bauer (’05) spoke of certain gaps or spaces between the meshes 
of the mesenchyme of the villi which he thought might belong 
to the lymphatics or contain tissue fluid. In these spaces he 
found certain granular, round cells arranged longitudinally. He 
thought they often were spherical with a diamenter of 10.5 u to 
12.5. but more commonly star-shaped or branched. By means of 
these branches they come into direct relation with other similar 
cells or with connective-tissue cells. However, Happe (’06) 
stated that he could not with certainty find cells united by their 
processes, as described by Hofbauer, in preparations stained 
after Hansen. According to Hofbauer, the cell processes are 
delicate, and the cells contain one or two nuclei from 4.7 u to 
5.7 « in diameter, oval or circular in form, eccentric in position, 
with a definite membrane and a dense chromatin network. Mi- 
toses were common, and fragmentation of nuclei and indications 
of pluripolar mitoses also were seen. Hofbauer emphasized that 
the most characteristic thing in these cells which he regarded 
as being specific was the presence of vacuolation in the ‘plasma’ 
and the existence of a perinuclear clear zone, which was said 
to be the result of fusion of ‘small light spots.’ As the cyto- 
plasm becomes vacuolated the nucleus is said to become pyc- 
notic, which stage is followed by failure to stain and finally by 
complete disappearence. Hofbauer also noticed the presence 
of granules and fat droplets, and regarded the life history of 
the cell as a circumscribed one. He did not find them present 
in real young villi. They were said to appear at the end of the 
fourth week, and were more common in young than in old placen- 
tae. They reacted to vital stains like plasma cells, and Hof- 
1A rereading of Stoffel’s article shows quite conclusively that he did not de- 
scribe the plasma cell of Hofbauer. 
