1886.] 



Structure of Mucous Salivary Glands. 



365 



glands wholly mucous. Glands with demilunes are simply glands in 

 which the " albuminous " element is reduced to a minimum. > The 

 apparent increase in size of the demilunes, described by Lavdowsky* 

 as taking place in the first stage of secretory activity, I take to be 

 due to the decrease in the size of the alveoli, so that the ordinarily 

 flat demilunes become more spherical. Moreover, the demilune cells 

 show signs of secretory activity ; in the submaxillary gland of the 

 dog after prolonged secretion the demilune cells, in section of the 

 gland hardened in alcohol, are smaller, they stain more readily with 

 carmine, and their nuclei and nucleoli are more conspicuous. The 

 "young" cells described by Heidenhain and by Lavdowsky are, I 

 think, chiefly altered mucous cells. 



The network of the cell consists of two parts, one in the cell-mem- 

 brane, the other stretching from this throughout the cell. The 

 peripheral network is best seen in the isolated cells of the orbital 

 gland of the dog after treatment with chloral hydrate, 2 per cent., for 

 a week to a fortnight. It consists of very delicate fibres ; at some of 

 the nodal points there are small spherical swellings. From lumen to 

 basement membrane there are twelve to fifteen meshes. In many 

 cases this network is perfectly distinct, every fibre in it can be 

 followed without the slightest difficulty. In such specimens, on the 

 other hand, it is often difficult or impossible to make out any cell- 

 membrane. That a membrane exists I conclude chiefly from observing 

 cells isolated in sodium chloride, 5 per cent., and then treated with 

 osmic acid. In such specimens the outline of the cells although 

 beaded appears to be continuous. The beading of cell-membrane has 

 been noticed by Schieffer decker ;f it is obvious with most methods 

 of treatment, it is caused by the fibres of the network, seen in optical 

 section. 



The internal network is connected with the peripheral network, 

 but it appears to me to have much larger meshes. From basement 

 membrane to lumen there are in the submaxillary gland of the dog 

 four to six meshes, in the orbital gland of the dog five to seven 

 meshes, i.e., the number of meshes in a given direction in the cell is 

 about half that of the number of granules. This network is seen on 

 treating with dilute mineral acids fresh cells which have been teased 

 out in sodium chloride, 5 per cent. ; it is seen more or less distinctly 

 in cells treated with the ordinary dissociating agents, and is seen after 

 hardening in various reagents. The reagent which I have found to 

 give most constantly satisfactory results, is a mixture containing 

 0*3 per cent, of chromic acid and 0*1 per cent, of osmic acid. 



The network which I have described above as the limiting network 



* Loc dt. 



t Max. Schultze's " A^chiV," Bd. xxiii, p. 382, 1S84. 



