THE ORGANS -OF DIGESTION. 



267 



rotates so that its left surface, with the left vagus nerve, comes 

 to be anterior ; the other posterior. 



(3) To allow this rotation to take place and probably for some 

 other unknown reason, part of the dorsal mesogastrium, which is 

 attached to the great curvature or dorsal border of the stomach, 

 undergoes a rapid growth and forms the great omentum (Fig. 2 1 4). 



The stomach loses its original vertical position only to a slight 

 degree ; even in the adult the pyloric orifice lies not far from 

 the middle line ; the oesophageal slightly to the left of it. The 

 glands of the stomach begin to form during the third month. 

 They appear as tubular invagination of the gastric hypoblast. 

 The peptic cells are formed by the 7 th month. 



The Spleen. — The Spleen appears in the dorsal mesogastrium 

 above the cardiac end of the stomach (Fig. 216) and grows 

 out on the left surface of the mesogastrium (Fig. 217). It 



diaph. 



liuer Ll—J^-'i-'W^i 



ventral mesent 

 (falc. lig.) 



umb. vein 



vit, duct — y ' 



gastro-hep. oment. 

 gastro-spl. oment. 

 spleen 



dorsal mesogastrium 

 stomach 

 great oment. 



■pancreas 



%- — mesentery 



rectum 



Fig 216 -The Relationship of the Spleen, Pancreas, and Liver to the Mesogastrium 

 in the Embryo. 



appears at the end of the second month by a collection of 

 lymphoid follicles in the mesoblast of the mesogastrium. The 

 tail of the pancreas (Fig. 216) reaches its point of origin. The 



