On the Histogenesis of Gastric Glands. 475 
are believed to develop (1) from the surface epithelium, (2) from 
special embryonic cells interpolated between the basal parts 
of the ordinary surface epithelium, or (3) from mesodermic cells, 
such as leucocytes. 
Group 1. Of those who describe the glands as originating as 
downgrowths of the surface epithelium, several have considered the 
all-important factor in early adeno-genesis to be irregular growth 
of the mesoderm, first manifesting itself as upgrowths, in the form 
of either villi or ridges. These coalesce or intersect, thus giving 
rise to intervening cul-de-sacs, the rudimentary glands. Of course 
the surface epithelium multiples to keep pace with the increasing 
area of mesoderm it must cover, but, by convention, this activity 
is considered secondary to that of the mesoblast. (For details 
vide Laskowsky ’68, Schenk ’74, Brand ’77, Sewall ’78, Baginsky 
’82, Kolliker ’84, p. 360, Negrini ’86.) Observations recorded 
in part 2 of this paper explain, we believe, the discrepancies of 
opinion regarding the exact nature of these mesodermic irregu- 
larities, 7. e., whether villi, papillae or ridges. Ko6lliker (’52-’61) 
Toldt ’81 (pylorus of cat) Patzelt ’84, Griffini and Vassale ’88, 
and Salivoli ’90 believe that the epithelium displays the initial 
activity, and that the glands may be said to have an intra-epi- 
thelial origin, irregular growth of mesoderm later becoming a fac- 
tor in bringing the glands to their definitive form. Thus, Kolli- 
ker, in ’52—’61, described the downgrowth of solid plugs of epi- 
thelium, which later acquire a lumen; he discarded this view 
(84), nor has it since been advocated. Griffini and Vassale des- 
cribe the gland as originating from the surface epithelium, as a 
funnel-shaped evagination, sinking down into the mesoderm. 
The deepest cells, being in continual mitosis, constitute an apical 
growth point. Only at a comparatively late stage does unequal 
mesodermic growth participate. According to Salvioli (90, 
rabbit), at an early stage (4 em.), while the basement membrane 
is yet perfectly level, intersecting ridges of epithelial cells rise 
above the general level of the epithelium. The intervening 
depressions are the rudimentary tubules. Later (6 cm.), these 
epithelial ridges are reinforced from below by cores of connec- 
