STRUCTURE OF THE MUCOUS MEMBRANE. 
289 
leaving shallow depressions or foveolae between them ; and 
at the bottom of these foveolae, generally three in number, 
are seen the openings of the gastric follicles. The openings 
of the gastric follicles are oval in shape, about 2T00 °f an 
inch in long diameter, and disposed irregularly in the foveolae, 
two or three in each ; so that the entire number of gastric 
follicles opening into each alveolus would amount to from six 
to ten or twelve. 
Large Intestine . — The surface of the mucous membrane of 
the large intestine presents this most obvious difference from 
that of the stomach, namely, smoothness, — a difference which 
is as apparent to the naked eye as to the eye armed with the 
microscope. With the microscope, moreover, we are struck 
with the symmetry of the reticulum and alveoli, by the 
greater breadth, lesser degree of prominence, by the flatness 
and evenness of the septa, and by the elliptical form and 
shallowness of the alveolar spaces. 
Fig. 2. 
A portion of the mucous membrane of the large intestine, magnified 75 
times. The alveoli measured 553 of an inch in length, by in breadth ; 
the septa between the alveoli measuring ^ of an inch in width. The 
alveoli are less regular in form and shallower than those of the stomach ; 
and in the bottom of each is a gland with a central excretory aperture. In 
some of the larger alveoli there are two glands. 
The septa measure about g-J^ of an inch in breadth ; and the 
alveoli of an inch in length, by ^ in greatest breadth. 
The septa contain a plexus of capillaries, smaller in size than 
those of the septa of the stomach, and having minute areolar 
spaces. The brim of the septum exhibits a small, chain-like 
plexus, composed of two or three of these capillaries lying 
parallel with each other ; the meshes of the plexus are oblong, 
and about equal in breadth to that of the capillaries. The 
alveoli are shallow, the floor being slightly convex, and occu- 
pied by a mucous gland having a central excretory aperture ; 
in some of the longer alveoli there are two glands and two 
excretory openings. 
XXVIII. 
37 
