DEVELOPMENT OF THE LARGE INTESTINE 



207 



Fig. 6 Longitudinal section of the transverse colon of a human embryo of 187 

 mm. X 60. Shows state of normal contraction (compare villi and glands with 

 those of fig. 7). 



Fig. 7 Cross section of the transverse colon of a human embryo of 190 mm. 

 X 60 (compare with fig. 6). 



that the circumference of one is greater in one than in the other, 

 because in the younger stage the epithehal wall is thrown into 

 three or four large folds. In order to determine accurately 

 whether the folds alone would compensate for so great a differ- 

 ence in diameter, enlarged camera drawings were made, and 

 the length of the lines at the bases of the glands (the line at which 

 the muscularis is just beginning to appear) was measured. The 

 distended gut (190 mm. stage) measured 15.3 mm., while the 

 contracted one only 11.3 mm., showing still a considerable un- 

 accountable difference. From what I have seen in this and 

 other sections, in the small as well as in the large intestine, I 

 have come to the conclusion that wherever the embryonic intes- 

 tine is greatly distended with meconium, as is often found to 

 be the case in the older stages, the thickness of the mucosa 



