OBSERVATIONS ON STRUCTURE OF CELLS AND NUCLEI. 151 



phagus be examined iu sections of specimens hardened in spirit 

 and stained in logwood, it will be seen that the cells lining the 

 alveoli are beautiful columnar cells having almost the same size 

 in the same alveolus ; these vary, however, amongst each other, 

 both as regards the diameter of their lumen and the lining cells, 

 as will be mentioned below. The cells are in all cases open, 

 their free surface not being covered by any membrane. They con- 

 tain an exquisitely beautiful network of fibrils which uniformly 

 pervades the cell substance, and which can distinctly be perceived 

 with even a D of Zeiss, or i of Crouch (see fig. 4, Plate 

 VII). In some alveoli I can distinguish also here an inner more 

 longitudinally striated part from an outer one with a uniform 

 network, but the number of such cells is relatively small, and 

 is to be met with only in alveoli in which no actual secretion is 

 going on (see below) . When viewing the cells from the surface, 

 — /. e. when viewing the mosaic formed by the ends of the cells 

 — the network is equally distinct. Some of the cells like those 

 in the submaxillary gland possess a process with which they 

 are imbricated on the membrana propria. The nucleus is recog- 

 nised as a shrunken deeply-stained body pressed against the mem- 

 brana propria, and situated usually in one of the corners of the 

 cell, that is to say, the cells resemble goblet cells. When viewed 

 from the surface the nucleus appears more or less rounded in 

 shape, and in some instances contains a uniform network. 



The membrana propria of the alveoli is very distinct. In our 

 sections it appears as a bright membrane, with staif-shaped 

 nuclei from place to place. The membrane being thicker where 

 a nucleus lies, we obtain the appearance of attenuated "'cre- 

 scents," such as described by Boll in the submaxillary gland, and 

 (as mentioned above) found also by von Ebner in the glands that 

 we are dealing with. Such is invariably the character of the 

 cells and membrana propria, no matter in what state the gland 

 is, viz. whether filled with mucin or not. The following two 

 conditions of the alveoli and tubes of the gland of the tongue 

 may be noticed : 



\d) The cells lining the alveoli do not contain any mucin, the 

 interfibrillar or interstitial hyaline substance (contained in the 

 intracellular network) remaining unstained in hasmatoxylin, but 

 the network is very distinct. The lumen of the alveoli and ducts 

 is empty. The alveoli differ in size to a considerable extent : 

 from alveoli of 0*04 mm. in diameter, and a lumen of 0*01 mm., 

 to such that measure 0-054 mm. in diameter, and O'OIS m 

 lumen. The length of the cells varies between 0-015 to 0*02 

 mm. (i) The cells are filled with mucin ; they stain, therefore, 

 a more or less deep purple-blue tint ; so do also the contents of 

 the lumen of the alveoli and ducts, these contain the same sub- 



