Mucous Membrane in the Human Embryo. 531 
duct. The excretory duct of the gland passes through the thick 
muscularis muscosz at nearly right angles to the surface epithe- 
lium. On reaching the outer border of the muscularis mucosae, 
it bends to either side. Instead of pointing toward the stomach, 
as has been described in the adult cesophagus (Goetsch), glands 
may extend either upward or downward. The distal termina- 
tions of most of the glands are expanded and lined by a simple 
glandular epithelium of low columnar cells. In the gland A 
(fig. 9) the end piece shows a number of bud-like processes which 
are the beginnings of branches. The end piece of gland B is a 
simple curved expanded tube, the expanded portion being for 
the most part glandular. In the gland C there is no end piece at 
all, the whole gland being lined by two layers of non-secreting 
low cuboidal cells. In a study of the cesophageal glands of the 
pig, Flint has described a similar early stage, in which the glands 
contain no secreting cells. However, glands of this type are 
rather rare in the human embryo at birth, there being a prepon- 
derance of those with secreting cells and beginning branches. 
In summarizing the development of glands of the cesophagus, 
it may be said that the first evidence of the cardiac glands is the 
appearance of small patches of glandular cells in the surface 
epithelium. These patches occur at both the upper and lower 
ends of the cesophagus and are seen as early as the third month. 
Later, by evagination, small pockets are formed from these patches. 
This.is followed by a subsequent budding from the outer; surface. 
Thus are formed,a number of branches which open into a single 
pocket. or ampulla... Cardiac glands never extend. through the 
muscularis, mucosae... The deep cesophageal glands, first seen, in 
an embryo of 240 mm., are outgrowths of the stratified squamous 
epithelium, which after piercing the muscularis mucosae, bend 
co either side, and lie-in the submucosa close to the muscularis 
mucosae.. The,seereting cells do not appear until after the gland 
is well formed, and.are found only near its distal termination. 
Here at, birth a number of budding processes, lined with a secre- 
tory epithelium, are seen arising from the end pieces. Thus the 
cardiac glands and the cesophageal glands differ in that, in. case 
of the cardiac glands the secretory epithelium appears before the 
