150 DR, E. KLEIN. 



larynx of dog and rabbit, this author found besides alveoli con- 

 taining mucous and " granular " cells also such that are lined 

 with only "granular" cells. 



V. Ebner^ investigated the mucous glands of the tongue of 

 man and the various domestic animals, and he found that the 

 alveoli are lined with glassy columnar cells of a granular contents, 

 which is mucous; the nucleus is generally indistinct, but 

 after reagents is seen as a small roundish or elliptical flattened 

 body next the membrana propria. This author mentions a dif- 

 ference between the mucous glands of the tongue of carnivorous 

 animals, on the one hand, and those of the tongue of rabbit 

 and guinea-pig on the other, consisting in the presence of cres- 

 cents in the former ; in the latter they are absent. But v. Ebner 

 adds, that these crescents are not comparable to the groups of 

 granular cells in the submaxillary gland of dog, which Heidenhain 

 spoke of as forming the crescents, but that they correspond to 

 thickened (nucleated) parts of the membrana propria, i. e. to what 

 Boll (loc. cit.) mentioned as "crescent" in the submaxillary gland. 



Tarchetti^ describes in the mucous glands of the trachea two 

 distinct forms of gland cells ; one corresponding to mucous cells, 

 the other to the more opaque protoplasmic parietal cells ; the 

 latter in some places completely occupy parts of the alveolus, 

 in others they are reduced to " crescents.''^ 



Ladvowsky examined the mucous glands of different regions 

 (oral cavity, larynx and pharynx), and he describes^ the changes 

 they undergo when their secretory nerves are subjected to stimu- 

 lation (electrical or chemical). These changes are in all respects 

 similar to those that he found in the submaxillary and orbital 

 glands, subject to the dift'erence that the above mucous glands do 

 not contain any (protoplasmic) parietal cells. The changes are 

 these : the nucleus becomes rounded and enlarged, then the sub- 

 stance of the mucous cells loses its mucous character, " owing to 

 the increase of their protoplasm ;" the cells become gradually 

 smaller and granular. In consequence of this alone the alveoli 

 become smaller. 



I have examined mucous glands in man and the domestic 

 animals of different parts of the body — tongue, palate, pharynx, 

 oesophagus, larynx and trachea, and I have arrived at the 

 conclusion that, as in the submaxillary gland of dog, the gland 

 cells possess different morphological characters during rest and 

 secretion, which (characters) in some respects correspond to 

 those mentioned by Heidenhain and Lavdowsky of the mucous 

 glands, but in other respects differ from them. 



a. In the dog. — If the mucous glands of the tongue or oeso- 



1 L. c, p. 19. 



- ' Kivista di Mediciua,' &c., December, 1874, 



3 L. c, p. 335. 



