316 STUDIES ON PATHOLOGIC OVA. 



branching might occur even at right angles, and that terminal branches which do 

 not reach the placenta remain free. These free endings were said to be present 

 in placentae of all ages, and to be filiform, cylindrical, pear-shaped, or club-shaped. 

 Branching was said to be so frequent and the interlacing of these branches so 

 common that only narrow intervillous spaces could be preserved in the placental 

 area. Kolliker particularly distinguished branches which he called fastening 

 rootlets (Haftwurzeln), which, according to him, were described by Ercolani and 

 also by Langhans. These were said to always enter the placenta and to become 

 attached to it so firmly that only considerable tension can separate the chorionic 

 vesicle from the placenta. Kolliker stated that these fastening rootlets are com- 

 monest near the septa of the maternal tissues which separate the cotyledons, but 

 that they nevertheless are found also in the center of the latter. 



Kastschenko (1885), in a careful study of the epithelial covering of the villi, 

 stated that they become more numerous in the region of the serotina by the end 

 of the second month, and believed that villi grow only by means of terminal and 

 never by lateral buds. 



Minot (1889) accepted the opinion that villi are hollow during the earliest 

 stages of development only, and stated that the villous nodules are especially 

 common in older placentae. In speaking of the collaginous tissue (Gallertschicht) 

 composing the inner portion of the villi, Minot stated that it usually contains a 

 considerable number of large, uninucleated, granular wandering cells, now fre- 

 quently spoken of as Hofbauer cells and discussed more fully in the previous 

 chapter. 



Giacomini (1892), in describing a young tubal conceptus, the villi of which 

 were not evident macroscopically, apparently regarded some of the syncytial 

 buds as representing young villi, and later (Giacomini, 1893), when considering 

 chorionic vesicles devoid of an embryo, which had evidently undergone hydatiform 

 degeneration, again spoke of the presence of many syncytial buds, some of which 

 he again interpreted as being young villi. 



De Loos (1897), who had no material from the first 6 months, believed that all 

 early conceptuses are covered completely by villi which are solid epithelial buds in 

 the earliest stages. He further believed that "they become hollow later and 

 are invaded by mesenchyme after vacuolation of the syncytial buds has prepared 

 the way for this invasion. According to de Loos, all villi in contact with the 

 decidua basalis become vascularized, and he distinguished between stem, or original, 

 and fastening or nutritional villi. From a study of cross-sections of villi, he 

 concluded that the number of villi with small caliber increases from the third to 

 the fifth month, and that the caliber is greatest at the fourth month. De Loos 

 also thought that the caliber of the villi decreases with the branching, and that 

 there are relatively more villi of small caliber in full-term placenta?, which he 

 regarded as evidence that new villi are constantly arising. Since Wiskott (1882) 

 had found only syncytium present on villi at the sixth month, de Loos concluded 

 that villi in older placentas which still are uncovered by epithelium necessarily 

 are hollow. 



