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, 
Fic. 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. 
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 
