THE ORIGIN AND DEVELOPMENT OF GASTRIC GLANDS. 85 



rounding it, represents merely the excretory duct and, perhaps, 

 the neck, while the fundus of the gland is to be sought for in the 

 aggregation of cells he has portrayed at the base of his so-called 

 gastric gland. Or this may be but one of the longitudinal ridges 

 and depressions, cut transversely, which abound in the oesophagus 

 but are less numerous in the stomach proper, though at an early 

 stage they are seen here also. 





' rS .-- ' - Gvvr^-'-w'TV.V ;-;-. ; .-'- - - ' ". -f^ys /. "\- -,>j .;<-.; 



/ : .o /9 : -^ : ^m^ M4 ' $?: '. -. *?% >&&$ /'..:' 



S^; l ; $iidli i If * ''<? " 



^^;;^.:^V;'^;^ x ^-'^\^,^ii >'"', ^5^1 





v : I, ':'?% 



FIG. 22. a. shows a gland fundus almost fully formed while as yet the epithelial 

 cells, ep., are full of yolk, y. , and the duct, d. , is still a shallow pit; /. , lumen. 

 The gland reaches almost to the free surface of the stomach. Obj. T ' s , Oc. 2. 



The general course of development of the earlier stages of the 

 gastric glands of the pig takes place in exactly the same manner 

 as in the simpler forms already described. As early as in an 

 embryo pig of 2 cm. total length, round, granular cells appear, 

 differing from the remainder of the epithelial cells by their struc- 

 tural appearance and also by their characteristic staining reaction 

 when stained with hematoxylin and eosin. The cells lining the 

 stomach are so closely packed together that they appear to be 



