480 Edwin G. Kirk. 
HISTOGENESIS OF THE GASTRIC GLANDS OF THE PIG 
1. The early stages 
The stomach of a 2 em. pig is about 2 mm. long. The cephalad 
part just left of the oesophagus has already been partially folded 
off as the secondary cardiac pouch (Coecum) being now separated 
from the main lumen by a fold which isolates it.2. This ridge is 
an infolding of all the layers, including the tunica muscularis, 
the latter and the connective tissue coat being also thickened at 
this point. 
A definite basement membrane separates epithelium from 
mesoblastic coats. This stains densely with Rubin §, and has a 
fibrous structure. 
The mesoblast has already differentiated into the connective 
tissue layer, the tunica muscularis and the serosa. Only the first 
concerns us. It is a typical mesenchyme, with numerous stellate 
and spindle cells, anastomosing by their processes. The nuclei 
are spherical, ovoid or elongated and many are in mitosis. The 
ground substance is transparent and gelatinous. Already this 
connective tissue coat has definitely differentiated into two 
strata (fig. 1). 
The cells and nuclei of the inner layer, just beneath the base- 
ment membrane, are very closely set, almost touching. Mitoses 
are very numerous. There is here but little of the mucoid, inter- 
cellular matrix, and it is dense, staining somewhat reddish or 
purplish with the three color or H & E. The blood vessels are of 
capillary size only. The endothelial cells of the vessel walls are 
very frequently mitotic. This layer is the young lamina propria 
mucosae. 
Outside this is a broader zone with cells and nuclei sparsely 
distributed, and a corresponding predominance of intercellular 
substance, the latter staining hardly at all, and being very clear 
and transparent. Mitoses occur, but are rare. Blood vessels 
are very numerous and many of them are of large size. This coat 
2 For the topography of the adult stomach, reference may be made to Green- 
wood’s accurate diagram, Fig. 252, Oppel, 1896. 
