362 THE PHYSIOLOGY OF REPRODUCTION 



disappear at parts. The nuclei are numerous, and most of the 

 authorities agree on the absence of mitoses, some holding that 

 they divide directly, others that they have lost the power of 

 division. The protoplasm has a foam-like structure, and in 

 Man it is condensed superficially to form a layer which bears the 

 " Biirstenbesatz " or striated border (Fig. 75). This consists, 

 as seen in fixed specimens, of a series of fine striae running per- 

 pendicularly to the surface, and its structure and function have 

 been much discussed since it was first described by Minot. 1 



I Si I' 



'2frF^ _ 



&. 



# : ^ 



.;^;?*A * 



FIG. 75. Part of an early human chorionic villus. (From Hofbauer's 

 Biologie der menschlichen Plazenta, Braumiiller. ) 



b, Biirstenbesatz with basal corpuscles ; s, syncytium ; I, Langhans' layer, 

 one cell dividing mitotically (I'}. 



Some have denied its existence during life, and ascribed it 

 wholly to the method of preparation. But Hofbauer 2 has 

 shown that the fresher a specimen is when obtained, the easier 

 it is to demonstrate the striae by methods of staining, and, 

 therefore, it is probably a vital structure. Kastschenko looked 

 on the stria3 as fine hairs which projected from the surface of 

 the cells, and by their vibrations created a stream in the maternal 

 blood of the intervillous spaces. In specimens stained with 

 iron-hsematoxylin, knobs may be seen at the bases basal 

 corpuscles or blepharoblasts and they may constitute the 



1 Minot, "Uterus and Embryo," Jour, of MorphoL, vol. xi., 1889. 



2 Hofbauer, Biologie der menschlichen Plazenta, Leipzig, 1905. 



