204 FRANKLIN PARADISE JOHNSON 



In the trans\'erse colon of an embryo of 110 mm, (f\g. 5), the 

 viUi are long and narrow, and give to the colon the appearance 

 of a small intestine of a slightly older embryo. Some of them 

 measure as much as 0.3G to 0.45 mm. in length and a\'erage 

 about 0.09 mm. in diameter at their bases. They are covered 

 by a low columnar epithelium (cuboidal in places), which is 

 rather poor in goblet cells. The glands are longer than those 

 of the preceding stage, being about 0.13 to 0.16 mm. in length. 

 The cells which line the glands are distinctly columnar, meas- 

 uring from 0.022 to 0.028 mm. in height. By far the majority 

 of these are goblet cells. Their nuclei are basally placed and 

 closely crowded together, making this region of the gland very 

 deeply stained. 



In the ascending colon, a similar picture is obtained. The 

 villi are, however, somewhat shorter (0.27 to 0.36) mm. Notice- 

 able again is the greater distribution of goblet cells in the glands 

 than on the villi, and the dilTerence in the height of the epithe- 

 lium in the two regions. In the sigmoid colon and the rectum, 

 the epithelial tube is larger and flattened from side to side. The 

 villi and glands are quite similar as regards size, shape and struc- 

 ture to those in the ascending colon. No epithelial cysts were 

 found in the piece of rectum examined, which was a portion 

 taken rather high up. 



In a well jireserved embryo of 120 mm., the transverse colon 

 has a diameter of about 1.08 nmi. in contrast to 1.26 mm. in 

 the preceding embryo. The villi, which are closely packed 

 together, are also shorter (0.18 to 0.27 mm.) than those of the 

 former embryo, but the glands are of about the same length. 

 This difference in size is probably due in part to the different 

 preservating fluids used on the two embryos. The epithelium 

 of both villi and glands is in excellent state of preservation and 

 the goblet cells, which have taken the stain (orange-O) very 

 strongly, stand out in marked contrast to the remaining cells. 

 It is easily seen, therefore, that the goblet cells are more numer- 

 ous on the sides than on the tops of the villi and most numerous 

 in the glands. In many glands these cells appear to be 

 exclusively present. Although the glands are still only short 



