12 MICRO-CHEMICAL REACTIONS OF GLAND CELLS. [BOOK II. 



In addition to the characteristic mucous cells there are found in 

 the alveoli of some mucous salivary glands when examined in a 

 state of rest, situated at some parts of the periphery, i.e. lying more 

 internal than, or nearer to, the membrana propria than the mucous 

 cells, small cells, possessed of a round nucleus usually aggregated 

 together, and containing much albumin ; to these aggregations (first 

 described by Gfianuzzi 1 ) the term demilunes or lunulce has been 

 applied. They may with probability be regarded as albuminous 

 cells which have been overlapped by the larger mucous cells. 



Microche- * ^ ne serous ce ^ s possess micro-chemical reactions 



micai reac- which indicate the presence within them of proteids ; 

 tions of the to wit, the addition of dilute mineral acids (containing 

 serous and Q-Q2 per cent, of acid) causes marked turbidity, an 

 lls> effect which is much more strongly produced by the 

 same acids in a concentrated condition. Acetic acid causes con- 

 siderable swelling and a clearing up of the cell contents. 



2. Mucous cells appear to be composed mainly of mucin or 

 mucigen (?). Their substance is precipitated by acetic acid, whilst it 

 is altogether unacted upon by strong mineral acids. 



3. According to Nussbaum 2 the presence of amylolytic ferment 

 within the secreting cells of the salivary glands is rendered evident by 

 the cells assuming a dark colour when brought in contact with a 1 per cent. 

 solution of osmic acid. It has however been shewn by Griitzner 3 that 

 the cells of salivary glands, which form no diastatic ferment, as for 

 instance the submaxillary gland of the rabbit, possess the property of 

 reducing osmic acid. Langley 4 has shewn that if a judgment as to the 

 cells which form diastatic ferment were based upon the osmic acid reaction, 

 we should be led to the absurd conclusion that the ferment is chiefly 

 formed by the epithelium lining the ducts and ductlets and the part of the 

 alveolus next to the latter, whilst the alveolar cells proper would enjoy no 

 such function. 



Some glands As has been said, in certain mucous glands the 

 intermediate mucous cells are supplemented by the cells of the demi- 

 in structure. l une s, though certain mucous glands, as those of the 

 tongue, exist where the typical mucous cells alone occur. 



There are glands, and the submaxillary of man is an example. 

 which are termed mixed glands, inasmuch as some of the acini have 

 all the characters of serous, others of mucous glands. 



1 Gianuzzi, Ber. d. Sachs. Ges. d. Wise., Sitz. f. 27 Nov. 1867. 



2 Nussbaum, 'Die Ferment-bildung in den Driisen.' Archiv f. micros. Anat. 

 Vol. xm. (1876), p. 721. 



3 Griitzner, ' Ueber Bildung und Ausscheidung von Fermenten.' Pfliiger's Archiv, 

 Vol. xvi. 1877, p. 105. 



4 Langley, ' Some remarks on the formation of ferment in the submaxillary gland 

 of the rabbit.' Journal of Physiology, Vol. i. (1878), p. 68. 



