HISTOLOGY 113 



the duct is lined by stratified squamous epithelium which toward the gland 

 changes into pseudostratified columnar type. The interlobular ducts are 

 lined by columnar epithelial cells. The intralobular ducts are the so-called 

 striated tubules, and are lined by rodded epithelial cells. These cells have 

 centrally located, large, round nuclei and characteristic basal striations in 

 their cytoplasm. The central intralobular ducts divide into terminal 

 tubules which in turn connect with the alveoli. The alveoli are composed 

 of "special serous cells" (18). They are pyramidal in shape and have 

 large, oval, darkly .staining nuclei near the bases of the cells. The granular 

 cytoplasm is basophilic and unlike the serous cells of the parotid gland it 

 does not contain chromophil substance (18). The cells rest on a basement 

 membrane. Scattered between this membrane and the epithelial cells, 

 stellate basal cells or "basket" cells are present. 



According to Oppel (Vol. Ill, 57) the submaxillary glands of the rat and 

 mouse are serous glands and do not contain any mucous cells. He states 

 that even those cells which resemble them are not true mucous cells. 

 Stormont (in Cowdry, 18) considers all the cells of the submaxillary gland of 

 rabbit, rat, mouse and muskrat as "special serous cells" and gives the 

 definition of this type of cells as "those non-mucous cells which differ in 

 important respects from the serozymogenic type but which, notwithstanding 

 a vast amount of research, remain, as yet, functionally and cytologically ill 

 defined." According to the same author the special serous cells forming the 

 gland of the mouse are of two types: "The gland tubules are composed of 

 tropochrome cells, but the terminal segments of the intralobular ducts con- 

 tain in their cells large coarse, highly refractive granules similar to those 

 present in the homeochrome cells of the rabbit's submaxillary gland." He 

 describes the tropochrome cells of the rabbit's submaxillary as clear, 

 palely stained cells which show coarse reticular structure. The nucleus is 

 usually shrunken and basal in position in fixed material. In preparations 

 fixed in sublimate these cells present an appearance very similar to mucous 

 cells, from which they differ by the fact that the contents of the cell spaces 

 do not stain with any of the ordinary staining reagents for mucin. The 

 homeochrome cells of the rabbit, according to him, have large oval nuclei 

 situated at the bases. Unlike the serozymogenic cells, they do not contain 

 chromophil material. The cytoplasm is abundant and filled with darkly 

 staining large granules. 



Our own observations which include the examination of the submaxillary 

 glands of more than 200 animals from the dba and C57 black strains showed 

 differences in the structure of the adult normal male and female animals. 



