334 ARTHUR WILLIAM MEYER 
consequently may be treated somewhat more fully. Renewed investi- 
gation has led me to the conclusion that we have to do with erythro- 
cytes which have gotten into the mesenchyma and, remaining there, 
have swollen by imbibition and are undergoing degeneration by vacu- 
olization of their protoplasm. . . . . We can explain the appear- 
ance of these cells by the assumption of imbibition, in which the 
nucleus has participated. . . . . Since I have found similar cells 
in a considerable number of placentas, I draw the conclusion that they 
are constant and normal. I regard the interpretation of the pictures 
unattackable as proof of progressive degeneration. — 
In association with these remarks, Minot represented a series 
of cells showing progressive degeneration, beginning with the 
nucleated red cells and ending with a highly degenerated, but 
nevertheless nucleated, Hofbauer cell which apparently is in 
process of disintegration. These cells were seen by Minot 
especially in a human embryo of 15-mm. length, from the Mall 
collection. 
As shown in the references to the literature above, it is not 
quite correct to say that the degenerate character of vacuolation 
has not before been recognized, for the surmises that Hofbauer 
cells contain fat granules may, and that they are swollen mesen- 
chyme cells must, carry this implication. Moreover, those 
familar with the effects of inanition know that investigators 
of this subject long ago called attention to vacuolation as one 
of the evidences of degeneration although, certainly, no one 
contends that it always is such. 
Instead of regarding these cells as degeneration products, 
certain Italian writers (notably Acconci ’14) regard cells which 
they found, especially in the first half of pregnancy, as morpho- 
logically and functionally comparable to the intersitital cells of 
the ovary and testis. Acconci believed that certain cells which 
he and other Italian writers after him designated lpoid-inter- 
stitial cells, probably produce a special internal secretion. He, 
like Hofbauer, found these cells to contain lipoid granules, and 
regarded them also as equivalent to certain cells “‘described by 
Ciaccio in various parts of the organism, or by Brugnatelli 
in the interstitial tissue of the mammary gland.” Acconci 
further emphasized certain similarities between the syncytium 
