26 



disproportionate development of entoderm may be interpreted in terms 

 of its phylogenetic history. The varying character of the epithehum 

 of the tubules indicates the presence of a fluid content exerting 

 pressure from within. This fluid appears identical — as judged by the 

 character of the coagulum — with that within the vesicle and both are 

 more probably a secretory product of the entoderm al cells. 



Branca (6) rejects this hypothesis on the grounds that "L'abon- 

 dance et la multiplicit6 des produits dont est charg6e la cellule 

 endodermique cadre assez peu avec cette explication". He describes 

 in the entodermal cells both of the main cavity and the tubules 

 "filaments polymorphes, qui se colorent avec Election par Th^mato- 

 xyline au fer". These are found in the basal portion of the cell. 

 He regards them as "protoplasma fonctionnel". They are thought 

 to play a role in the elaboration of the entodermal inclusions (yolk 

 granules and fat globules). The condition marked by their presence 

 is described as very transitory, being at its height in embryos of 

 about 9 mm to 11 mm, and not found in very young and in old 

 vesicles. The granular inclusions of the entodermal cells are said to 

 show affinity for acid dyes, and are regarded by Branca as albuminoid 

 substances, derivatives of liquid yolk, transformed by the entoderm 

 for the use of the developing embryo. He compares the basal cyto- 

 plasmic filaments ("functional protoplasm") to the ergastoplasm of 

 secreting cells, as found in the pancreas, liver, kidney, salivary glands, 

 testicle, etc. 



Branca notes, furthermore, that in the entodermal cells the 

 granular inclusions ("enclaves") increase as the bundles of basophile 

 filaments ("protoplasmas fonctionnels") decrease and vice versa. This 

 agrees with the behavior of the prozymogen (ergastoplasm) and zymogen 

 granules of secreting cells. 



In the entodermal cells of the umbilical vesicle of a 9,2 mm 

 human embryo I described certain masses which in position and stain- 

 ing reaction agree with Branca's "protoplasma fonctionnel" (Fig. 6). 

 On the basis of their reaction to Mayer's muchematin, I interpreted 

 them tentatively as mucinous bodies. The general character of the 

 cells suggested that they might be products of mucous degeneration. 

 Various cell inclusions were also noted, as other investigators had 

 done previously. These may include fat globules and probably also 

 glycogen (Paladino), cell detritus (Meyer) and albuminoid bodies 

 (Branca). The histologic character of the cells, as also the presence 

 of an amorphous coagulum in the vesicle and the tubules, indicate a 

 secretory function of the cells. I believe that Branca has more 



