112 The Cardiae Glands of Mammals 
varies with different individuals and in different portions of the zone in 
the same individual. The maximum extent is given by Kupffer, 83, 
as 1.5 em., the minimum as .5 cm. That the maximum may be much 
greater than this is indicated by the present case in which the cardiac 
glands begin nearly 3 mm. above the termination of the cesophageal 
epithelium and extend a distance of 4.3 cm. into the stomach. The 
latter measurement is following the various folds of the mucous mem- 
brane, the length in a straight line being 3.4 cm. 
The mucous membrane at different points in this region is of very 
unequal thicknesses, the differences in this respect being partly due 
to the size and mode of aggregation of the glands, partly to the number 
and size of the lymphatic follicles which, as Schaffer indicates, are very 
numerous. In general it may be said that the greatest thickness occurs 
at or near the cesophageal epithelium and the minimal at the point 
where the cardiac gland zone passes into the fundus gland zone. In a 
zone comprised within a distance of 2 mm. from the cesophageal epithe- 
lium the thickness of the mucous membrane, not including the museu- 
laris mucose, varies from .99 mm. to 1.826 mm. ‘Three millimeters 
from the cesophagus in one section which is fairly representative the 
thickness is .969 mm. From this point onward there is a gradual 
diminution in thickness until at a point 11 mm. from the cesophageal 
epithelium the minimum thickness of .5 to .6 mm. is reached, which is 
maintained, with slight variations probably due to different degrees of 
contraction of the intrinsic muscle fibers, for the rest of the cardiac 
zone. 
This great difference in the relative thickness of the mucous mem- 
brane of the proximal and distal portions of the zone is due to a differ- 
ence in the nature of the glandular aggregates, not to a fundamental 
difference in their structure. Just at the termination of the cesophagus, 
the glands consist for the most part of freely branched and tortuous 
tubules, derived from a narrow duct which ascends in the direction of 
the free surface of the mucosa to open alone, or more frequently in 
common with others, into a depression of the surface which corresponds 
to the ducts or foveole of the glands of the rest of the stomach. Sev- 
eral such tubulo-racemose glands are commonly grouped together into 
a sort of lobule more or less definitely separated from adjacent groups 
by a sort of septum of collagenic fibers containing bands of smooth 
muscle. The ducts of these glands are frequently the seat of retention 
cysts which may be of such a size as to be readily recognized without 
the aid of a microscope. These may oceur near the opening of the 
gland into the foveole or deeper in the mucosa. The cysts appear as 
large oval ampulle into which the branches of the gland open. The 
glands and ducts are lined throughout by secreting cells. 
