304 STUDIES ON PATHOLOGIC OVA. 



formig getheilt. Da sie stets nur in Gewebsliicken gefunden werden, so glaube ich, sie 

 als Lymphgefassendothelien, oder vielleicht als Lymphocyten bezeichnen zu diirfen. 

 Man findet sie in spateren Stadien der Placenta nur sind dann natiirlich die Zellen nicht 

 mehr gross." 



The illustration which accompanies Kworostansky's article, as well as his 

 description, leaves no doubt that the cells seen by him are the same as those which 

 we are considering, although his surmise that they are lymphocytes and that they 

 arise from the endothelium of the lymphatics may, upon first thought, seem rather 

 irreconcilable with such an assumption. 



From these references alone it is evident that Minot's statement that the 

 so-called Hofbauer cells were repeatedly mentioned in the earlier literature is well 

 founded. Muggia (1915) stated that these cells were described also by Guicciardi 

 (1899), Clivio (1903), Stoffel (1905), 1 Vecchi (1906), and Pazzi (1904). Indeed, 

 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 unrecognized cases of hydatiform degeneration, but since they have 

 been referred to as Hofbauer cells, it is his description that especially interests us. 

 In describing the chorionic villi, Hofbauer (1905) 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 granu- 

 lar, round cells arranged longitudinally. He thought they were often spherical, 

 with a diameter of 10.5 M to 12.5 M, 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 (1906) 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 M to 5.7 n in diameter, 

 oval cr circular in form, eccentric in position, with a definite membrane and a 

 dense chromatin network. Mitoses 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 

 cytoplasm becomes vacuolated the nucleus is said to become pycnotic, which 

 stage is followed by failure to stain and finally by its complete disappearance. 

 Hofbauer also noticed the presence of granules and fat droplets, and regarded the 

 life-history of these cells 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 placenta?. They reacted to vital stains like 

 plasma cells, and Hofbauer regarded the vacuoles as having an assimilative and 

 digestive function. A reference to the plates accompanying Hofbauer's mono- 

 graph, however, suggests that vacuolation was not always present, and that the 

 largest of the cells were almost twice the size of the smallest. 



1 A re-reading of Stoffel'a article shows quite conclusively that he did not describe the plasma cells of Hofbauer. 



