The Digestive System 



185 



of the animals from which the tissues were taken 

 than to the different conditions of hibernation and 

 feeding. The point to be 

 noticed is that the increase 

 in the diameter of the intes- 

 tine is due almost if not 

 entirely to an increase in 

 thickness of the connective 

 tissue and muscle layers. 



No difference in the com- 

 plexity of the folds of the 

 mucosa of the two stages 

 can be noticed. 



The thickness of the fibro- 

 muscular part of the wall of 

 the intestine varies consid- 

 erably on different sides of 

 the same region, but it con- 

 sists of the same layers in 

 about the same relative 

 amounts. 



Figure 51 represents in 

 outline the wall of the mid- 

 dle region of the small intes- 

 tine during feeding. 



The epithelium is of the same thickness in the 

 two stages, and the only difference in its character 

 that can be seen under a high magnification is that, 

 in the middle region at least, the nuclei are not 

 crowded so close together at the basal ends of 



Fig. 51. An outline of a 

 transsection of the wall of the 

 middle region of the small in- 

 testine of the feeding animal, 

 under low magnification; m, 

 mucosa; other letters as in 

 Figure 42. 



