GLANDULAR EPITHELIUM AND DIVISION OF NUCLEI. 407 



the outlines of the individual cells cannot be distinguished ; 

 in others they appear of the nature as represented in fig. 1 of 

 Plate XVIII, viz. of various sizes; their shape is either 

 cylindrical or, more commonly, truncated and conical, with 

 their base situated on the membrana propria. Some appear 

 uniform, others consist of (a) a transparent, apparently finely 

 granular substance, forming about one half of the cell in a 

 longitudinal direction ; (b) the other half is less transparent, 

 being filled with coarse, highly refractive particles. In sections 

 of hardened specimens (especially picric acid specimens) 

 stained with lisematoxylin or carmine the former is seen to 

 be an exceedingly dense network of very minute fibrils,^ 

 whereas the latter contains, in the meshes of a network of 

 curved and twisted fibrils, real granules and parti<;les of 

 various sizes. The nucleus is situated in many instances in 

 the transparent part, but next the membrana propria ; in 

 others it lies partly in the transparent, partly in the 

 granular portion, and in still others it belongs almost entirely 

 to the latter. See fig. 1, Plate XVIII. 



Other cells, especially those near the duct, ^. e. the fine 

 canal passing through the epidermis and formed by a single 

 layer of flattened nucleated cells, are almost completely 

 filled with spherical or elliptical or discoid globules of a 



^ Speaking of the epithelial cells lining the glands of the cloaca of 

 Triton, Leydig (I.e., p. 213) says, " They possess a vacuolated frothy aspect. 

 After reagents and using high powers, it can be ascertained that this is 

 due to a trellis- or network permeating the interior of the cell, that it origin- 

 ates from the protoplasma surrounding the nucleus, and that the larger 

 trabecule start as it were in a radial direction from the nucleus while the 

 finer ones lie in the periphery of the cell-wall." . . . 



" This peculiar structure of the cell may be placed side by side with what 

 I communicated ten years ago of certain large nuclei of the same animal." 

 . . . . "Ten years ago" would correspond to the year 1805 — the 

 above article having been evidently written in 1875 — and the communi- 

 cation was made in ' Vom Ban d. Thierischen Korpers,' a work which I 

 regret not to be able to procure. 



Leydig continues : "And I may expressly mention that this structure 

 of the cell may have a much greater distribution ; at any rate, I am able 

 to see precisely the same structure in the coloured blood-corpuscles of the 

 same amphibian species after acting upon them with Midler's fluid ; also 

 here a fine trelliswork passes radially from the nucleus to the periphery of 

 the cell, and at first sight presents itself as 'granulation.'" It appears 

 from this that Leydig was the first to recognise the reticular structure of 

 protoplasm and of the substance of coloured blood-corpuscles, having men- 

 tioned it already in 1SG3, before Erommanu 1867 and Heitzmauu 1873. 



It is, however, important to add that Leydig, as appears further on (1. c, 

 p. 227), regards this reticular structure merely as " a certain transforma- 

 tion of the protoplasm in consequence of the appearance of numerous 

 cavities." The trabecular or spongy matter represents "remains of the 

 original protoplasm attached to the cell-membrane." 



