27 



accurately described these basophile ("mucinous"?) masses as bundles 

 of filaments (they are not present in the older vesicle), and I am 

 even inclined to accept his interpretation of these as analogous to 

 «rgastoplasm (prozymogen). But that they bear any genetic relationship 

 to the large acidophile bodies of the cytoplasm seems very doubtful 

 for the following reasons: 1) The granules ("enclaves") are scattered 

 promiscuously through the cell. 2) Their angular and irregular form 

 and their frequently large size, find no analogy in the zymogen 

 granules of approximately uniform size and shape of the secretory 

 cells. 3) The disappearance of the filaments (ergastoplasm ?) con- 

 comitantly with the increase of the flakes accords better with the 

 hypothesis that after a transient stage of secretion a gradual degener- 

 ation ensues involving the destruction of the ergastoplasm or "functional 

 protoplasm" and the production of cell debris. 



Moreover, I cannot accept Beanca's hypothesis that the ento- 

 dermal cells of the umbilical vesicle form an organ of absorption, 

 "comme Tintestine", extracting "du milieu ambiant des substances, 

 qu'elle transforme et deverse dans les vaisseaux". Branca notes 

 various points of similarity between the umbilical vesicle and the 

 intestine: 1) Common origin from primordial entoderm of lining epi- 

 thelium; 2) close (structural?) analogy between umbilical entoderm 

 and intestinal epithelium in various points, viz: a) originally simple 

 epithelium and central position of nucleus; b) structural polarity of 

 «ell ; c) presence of basophile and lipoid bodies ; d) presence of tubular 

 glandular depressions, frequently cystic and lined with a similar type 

 of epithelium. 



But the analogy becomes unduly strained in one vital point. 

 While there are "ici et la des enclaves de nature vari6e", there appears 

 no cogent proof that their nature is identical. In fact the evidence 

 is against this view as above detailed. Moreover, the apparent 

 agreement is one of homology rather than analogy. This general 

 similarity is due to a common origin, but between the cells lining 

 the intestine and those lining the umbilical vesicle there is all the 

 difference between cells that function essentially as absorbing elements 

 and those that function as elements of secretion. There is here the 

 same difference in structure that obtains between the cells of the 

 intestinal villi, whose prime function is absorption, and the central 

 cells of the fundus glands of the stomach, whose function it is to 

 secrete pepsin. These cells arise from the same primordial entoderm, 

 and retain a general similarity of structure, but they cannot therefore 

 be said to have a similar function. Again, nothing resembling the 



