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DR. HERBERT WATNEY ON THE MINUTE 
(B) In preparations hardened in chromic acid, small cells are found at the base of the 
epithelium.' This fact was described by Todd and Bowman (32), who seem to have 
thought that a second layer was always present. F. E. Schulze (98) (Taf. x. fig. vi.), 
Ebstein (95) (fig. i.), and Bleyer (99) have also described small cells at the base of the 
epithelium. 
These cells are of two kinds : — first, lymph-corpuscles similar to those which have been 
described among the epithelial cells of the intestine (see fig. 28, Plate 42) ; and secondly, 
rounded or conical cells which are only found at the base of the epithelium (see figs. 
29 and 32) *. These latter cells have a faintly granular protoplasm, and contain spherical 
nuclei which are not readily stained by hgematoxylin. These cells may therefore be distin- 
guished from the lymph-corpuscles, which have been already described as consisting of 
a small clear zone of protoplasm surrounding a very deeply stained spherical nucleus 
(compare fig. 28 and fig. 29). 
(C) In similar preparations we find short broad epithelial cells, showing a faintly staining 
cell-substance containing a large pale nucleus, which may be divided (see fig. 30). 
(D) And, finally, we see groups of epithelial cells composed of two or three, or even more, 
cells arranged very much like a bud (see figs. 13, 31, 33, where it will be seen that the 
base of the group of cells projects slightly into the mucosa). These groups of cells are 
the structures which I propose to call “ epithelial buds.” 
The same features are seen in the small round or conical cells of figs. 29 & 32, and 
in the short broad cells of fig. 30, and in the epithelial buds of fig. 33. These features 
are a spherical nucleus, as opposed to the oval nucleus of ordinary epithelium, and a 
faintly granular protoplasm of the cells, which is not easily stained by heematoxylin. 
Now it seems to me reasonable to form the following conclusions from the appear- 
ances described at (A), (B), (C), (D) : — that the epithelial cells divide ; that the small 
rounded cells of figs. 29 and 32 are the products of their division ; that these small 
cells, increasing in size and rising up among the older cells, push them to one side, and 
form the short broad cells as represented by fig. 30 ; and that these short broad cells, 
by division, form the bud-like structures of figs. 31 & 33. The view that the buds are 
caused by division is favoured by the appearance of the epithelial cells next to the bud- 
like groups. They are always compressed together, are deeply stained in hematoxylin, 
and contain a considerable amount of mucus. 
* Pig. 29 is drawn from a preparation which had been stained in haematoxylin ; the upper part of the cells 
is seen to he intensely stained, and in the original preparation was of a deep blue colour. The cells are open 
and contain mucus. It is the mucus which has been stained so readily. That mucus is very readily stained a 
blue colour by haematoxylin, has been shown by me in a short note to the Royal Society (Proceedings, vol. xxii. 
p. 293). Thave there described the different manner in which the cells of the mucous glands of the tongue are 
acted on by staining fluids, in states of inanition and secretion. Specimens stained first in haematoxylin and 
then in carmine showed that during inanition the cells contain mucus, and their contents are more easily stained 
by haematoxylin than by carmine ; whereas during secretion the carmine will stain the cell substance more readily 
than haematoxylin ; any mucus in the ducts of the glands is, however, stained an intensely blue colour. 
