84 EDWATiD B. POULTON. 



obviously an interpapillary process between the small secon* 

 dary papilla. It now remains to describe the minute charac- 

 ters of the cells of the papillae and epithelium around, and the 

 relation of both to the hair-like papillse. 



When the mass of cells within the ring is cut vertically it is 

 at once seen to be divided into two chief layers, sharply 

 marked from each other. The upper stains deeply and the 

 cells appear homogeneous, the lower does not stain (or very 

 slightly), and the cells are extremely granular (figs. 4, 5, 11, 

 and also seen in horizontal sections, tigs. 6 and 12). 



The transition of characters met with in passing upwards 

 through the central mass of cells is very remarkable. The 

 mass may be divided into two chief parts (already indicated), 

 each of which may be further subdivided (see fig. 8 and de- 

 scription). From below these are (A) granular cells hardly 

 staining in picrocarmine or logwood. 



(1) The lowest columnar and succeeding small polyhedral 

 cells. The columnar cells are shorter than in the rest of the 

 epithelium, and both kinds of cell more granular with less 

 distinct outlines. Indications of karyokinesis are not un- 

 common. 



(2) The cells are fusiform and granular with indistinct out- 

 lines ; the nuclei frequently have a vacuolated appearance. 

 This is commoner over the secondary papillary processes 

 beneath the hair-like papilla? than over the convex interpapil- 

 lary part. 



(3) A very thick layer of cells with distinct outlines, fusi- 

 form in shape, attenuated below but much swollen above. The 

 contents are very large granules, arranged in groups or rows 

 in a fine granular matrix, staining slightly, and especially dis- 

 tinct at the margin, where a thin layer is generally free from the 

 larger granules. The nucleus is often indistinct, shrunken, and 

 sometimes absent, filled with large and small granules. The 

 large granules are rounded or angular, and do not stain at 

 all. (See fig. 9, a and b, for the outline of a swollen cell from 

 the upper part of this layer.) Attenuated cells often have a 

 single row of granules from end to end. 



