306 STUDIES ON PATHOLOGIC OVA. 



Instead of regarding these cells as degeneration products, certain Italian 

 writers (notably Acconci, 1914 b ) regarded cells which they found, especially in the 

 first half of pregnancy, as morphologically and functionally comparable to the 

 interstitial cells of the ovary and testis. Acconci believed that certain cells which 

 he arid other Italian writers after him designated lipoid-interstitial cells, probably 

 produce a special internal secretion. He, like Hofbauer, found these cells to con- 

 tain 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 and the interstitial cells, both of which he conceived as 

 exercising a protective role. Muggia (1915), too, instead of regarding the lipoid 

 interstitial cells of Acconci as degenerate, emphasized his belief that they are 

 particularly resistant to degeneration, being found perfectly preserved in the 

 midst of detritus. Since the young connective-tissue cell loses, or rather retracts, 

 its processes as it becomes converted into a Hofbauer cell, it need not surprise us 

 that the latter survives the former. Retraction of the processes contributes to 

 the apparent increase of cytoplasm of the rounded swollen cell and also is involved 

 in the formation of the spaces in which these cells usually lie. Muggia, who con- 

 sidered the cells found by him in great numbers in a case of partial hydatiform 

 degeneration as identical with those described by Acconci, gave a fine detailed 

 description absolutely typical of the cells previously described in greatest detail 

 by Hofbauer. Moreover, the excellent illustrations which accompany Muggia's 

 article leave no doubt as to the identity of the cells or of their degenerate character. 

 Muggia stated that these cells in normal villi increase until the end of the fifth 

 month, when, according to Savare, they are most numerous. Muggia further found 

 numerous cells very similar to the interstitial cells of Acconci, or "the plasma-like 

 cells of Hofbauer," which he says are regaredd by some as early stages of inter- 

 stitial cells and by others as mast-cells, concluding that he regarded the latter as 

 partially differentiated interstitial cells. 



Until I had seen sections of the chorion of No. 1531 I was largely at a loss to 

 know why Hofbauer cells were so frequently described as lying in gaps or spaces 

 in the mesenchyme. However, in this specimen cross-sections of a number of 

 villi showed splendid examples of this condition, which alone made the cells very 

 conspicuous. The cells often were very numerous, in fact more numerous than the 

 mesenchyme cells which remained, although some well-preserved villi contained 

 no Hofbauer cells whatever. Some of the younger specimens also contained none. 

 This was true of a chorionic vesicle with an embryo 1 mm. in length. They were 

 found most commonly in the villi, but not infrequently some of them lay in areas 

 of the chorionic membrane which had undergone degeneration. They were not so 

 common here, but sometimes were exceedingly numerous in small areas. They 

 were found in the amnion also, in the umbilical cord, and in the tentorium cere- 

 belli, and as isolated specimens in embryonic mesenchyme elsewhere. As em- 

 phasized by other investigators, there seemed to be nothing particularly character- 

 istic about their distribution, except that they were more common in places where 



