OBSERVATIONS ON STRUCTURE OF CELLS AND NUCLEI. 149 



From my experience of human submaxillary gland, above de- 

 scribed, I am in agreement with Boll and in opposition to 

 Lavdowsky ; but differing from Boll, I assume here not only a 

 change of the alveoli lined with granular cells into such as are 

 lined with mucous cells, but, vice versa, a change of mucous cells 

 into "granular" cells. 



Whether in my cases this change is observable in the abso- 

 lutely normal gland under normal conditions of function, or 

 whether it is found only so in consequence of prolonged secre- 

 tion — in the cases of scarlatina, from which the above glands 

 were derived, there was a considerable amount of throat affec- 

 tion, and hence most likely a prolonged secretion of all glands 

 leading into the oral cavity — must be determined by further 

 investigations. 



In the lobar ducts of the human submaxillary gland we find 

 that the epithelium is composed of a superficial layer of beau- 

 tiful columnar epithelial cells and a deep layer of small cells, the 

 former possess very elongated nuclei, the nuclei of the latter 

 being oval. The nuclei of both contain a uniform network of 

 fibrils, with the usual bright dots in the nodes, but no large 

 particles comparable to a nucleolus. The columnar cells show a 

 distinct bright striated border like the epithelial cells of intes- 

 tine, only not so broad, and I have ascertained that also in the 

 ducts of the submaxillary gland the bright border has nothing to 

 do with the striation, the former being sometimes absent, and the 

 latter can then be made out as being due to the ends of longitudinal 

 fibrils, of which the cell-substance appears chiefly to be made up. 

 But we find also here on close inspection that these fibrils form 

 a network. 



The lobular ducts possess the same rod-epithelium as in the 

 submaxillary gland of dog. 



4. Tke Epithelial Cells of Mticous Glands. 



The gland-tubes (Puky Akos^) of mucous glands are usually 

 described as possessing a relatively large lumen, lined by more 

 or less granular cells, whose nucleus is in some glands round, 

 and situated in the outer part of the cell, in others it is very 

 indistinct, being much compressed and close to the membrana 

 propria. 



Heidenhain, on the occasion of his investigations of the sub- 

 maxillary gland of dog (loc. cit.), pointed out that this gland is 

 in many respects similar to the ordinary mucous-secreting glands 

 of other parts, for he found also in some of these a distinction 

 between parietal "granular" cells and central mucous cells. In 

 the mucous glands of the lip of man and rabbit, in those of the 

 1 'Sitzungsb, d, k. Akad. d. Wiss.,' Band. 60, ii, 1869. 



