340 ARTHUR WILLIAM MEYER 
Since thirty-two of the fifty-one specimens in this series of 
sixty-one containing a few, some, or many Hofbauer cells had 
been classed among the pathologic, it follows that these cells 
were noticed more frequently in the pathological than in speci- 
mens classed as normal. This becomes especially evident if 
we exclude from this series of fifty-one cases all those contain- 
ing some or many Hofbauer cells, for of twenty-seven of these, 
nineteen, or 70.4 per cent, had been classed among the patho- 
logic. Moreover, since the great majority of the conceptuses 
classed as normal belong among abortuses, one would be en- 
tirely justified in questioning the strictly histologically normal 
nature of the chorionic vesicles which accompany some embryos 
classed as normal. At any rate, it is evident that the plasma 
cell of Hofbauer is associated with degenerative changes in the 
mesenchyme of the villi. Since such changes are more common 
in pathologic abortuses it is not surprising that Hofbauer cells 
are more common in the latter than in normal specimens, and, 
since degenerative changes in the stroma are especially pro- 
nounced in advanced cases of hydatiform degeneration, it is 
still less surprising that Hofbauer cells are particularly common 
in this condition. But they are not necessarily pathognomonic 
of hydatiform degeneration, although it is true that when at 
all numerous they are associated with hydatiform degeneration 
in about 75 per cent of the cases. 
A ter a careful survey of a considerable number of speci- 
mens, both normal and pathologic, ectopic and uterine, of 
human conceptuses of widely different ages, Iam led to concur 
entirely in the opinion of Minot that the typical vacuolated 
cell, as described by Hofbauer, is a degeneration product, though 
usually not a degenerate erythroblast, as Minot concluded. Rarely 
have I seen a chorionic vesicle in which the rather small, clear, 
isolated Hofbauer cells scattered throughout the stroma of a 
villus undoubtedly were erythroblastic in origin. In these villi 
capillaries in various stages of disintegration were present, and 
the erythroblasts could be traced directly to these degenerate 
capillaries. In the earlier stages of this degeneration these 
degenerating erythroblasts are not surrounded by spaces, how- 
