HOFBAUER CELLS. 305 



In his earlier paper Hofbauer (1903) also said that his preparations, taken 

 from material from the fourth to the ninth week of pregnancy and obtained at 

 operation, showed these cells in all stages of mitotic division. Hofbauer further 

 wondered whether the spaces surrounding these cells are lumina of capillaries, 

 added that the cells discovered by him undoubtedly are found in capillaries, and 

 made some rather unguarded surmises concerning them. 



Berlin (1907), in writing on the changes in retained placenta, also spoke of 

 large, swollen, hydropic cells which lie in spaces. These cells she regarded as un- 

 doubted mesenchyme cells. However, Berlin did not believe that they are de- 

 generation products, although her description certainly would lead one to suppose 

 that they were such. Even when she stated that they bear no sign of degeneration, 

 emphasizing that the chromatin network is fine, she nevertheless spoke of swollen 

 nuclei which have gathered a larger amount of protoplasm about them, phenomena 

 which she regarded as signs of luxurious nutrition. Moreover, Berlin never ob- 

 served mitoses and never found the nuclei increased, in villi containing many of 

 these cells, an observation wholly in harmony with that of others and directly 

 opposed to the idea of proliferation. 



Grosser (1910), who was plainly aware of the fact that Hofbauer was not the 

 discoverer of these cells, also represented a cell, which, however, is non-vacuolated 

 and binucleated, and added that their significance is still unknown. 



I have given Hofbauer's description, partly to emphasize the vacuolation, 

 for it was this which also impressed Minot (1911), who rightfully stated: 



"We frequently find in the literature mention of wandering cells with vacuolated 

 protoplasm, but they seem not to have been recognized as degenerating cells. . . . 

 The disintegration by vacuolation has, so far as known to me, not been described hereto- 

 fore, and consequently may be treated somewhat more fully Renewed in- 

 vestigation has led me to the conclusion that we have to do with erythrocytes which have 

 gotten into the mesenchyma and, remaining there, have swollen by imbibition and are 



undergoing degeneration by vacuolization of their protoplasm We can 



explain the appearance 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 Carnegie 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 mesenchyme cells must, carry this implication. Moreover, those familiar 

 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, cer- 

 tainly, no one contends that it always is such. 



