STRUCTURE OF THE MUCOUS MEMBRANE. 
415 
of epithelium) between and ^ of an inch in breadth ; 
the alveoli are very variable in size, -fo of an inch being a 
general average. An alveolus of small dimensions measured 
A °f an inch by - 7 V j while another measured ^ by -Jq. 
The reticular framework has the appearance of a very 
delicate membrane puffed up to its proper elevation, and 
pierced with numerous small angular and oval openings, the 
Fig. 6. 
A portion of one of Peyer’s glands, magnified nineteen times. The 
alveoli are deep, they measure A by ^ of an inch, and the septa between the 
alveoli measure from ds to 7 l 0 f an inch. A vascular network and the 
openings of numerous simple follicles are seen in the floor of the alveoli : 
and the septa are marked by numerous circular and elongated sulci. 
openings being the mouths of shallow pits, and resembling 
the depressions on some light material, such as muslin, pro- 
duced by the process termed (C quilting/’ These openings 
might, on a superficial observation, be taken for simple 
follicles ; but I am inclined to think that such is not the case. 
The reticular framework presents on the surface a rich net- 
work of capillary vessels with small meshes. 
The alveoli have a general squareness of form, but are in- 
dented upon the sides more or less deeply, and hence are 
very irregular in outline. Their size is about of an inch 
in diameter, and they are slightly longer in one direction 
than in the other. They are sharply cut along the margin, 
and about of an inch in depth. The floor of the alveoli 
is somewhat raised in the centre, and from this raised part 
are given off ridges or spurs, which radiate towards the circum- 
ference, and become continuous with the walls of the cavity. 
This structure reminds us of the floor of the alveoli of the 
stomach, and, like it, the raised portion and the spurs consist 
of a plexus of fine capillary vessels. The spaces or foveolae, 
between the spurs, from five to eight in number, are deeper 
than the rest of the floor, and in them are seen the apertures 
of follicles, two or three in each foveola : hence the entire 
