164 1)R. E. KLEIN. 



A. In the parotid : — (1) In the dog : the interlobular ducts 

 are lined with a double layer of epithelial cells, the outer layer 

 well developed; no distinct fibrillation of the cell-substance. 

 (3) In the ape : two layers of epithelial cells^ the outer layer of 

 cells not so well developed as the inner, the nuclei of the former 

 spherical, while those of the latter are oblong. The fibrillation 

 of the cell-substance is tolerably distinct. (3) In the guinea- 

 pig : two layers of cells, similar to those of the parotid of the 

 dog, only in alcohol specimens is there an indication of a fibrillar 

 structure of the oelUsubstance. (4) In the rabbit : two layers 

 of epithelial cells, the outer layer is very well developed ; traces 

 of fibrillation of the cell-substance. 



B. In the submaxillary gland : — (1) In the dog: two layers 

 of cells, the outer layer not well developed, the nuclei of its cells 

 spherical and small, those of the inner layer very crowded, 

 larger, and oval. No distinct signs of fibrillation in the cell- 

 substance. (2) In man there are two layers of cells, the outer 

 layer well developed ; its nuclei are here larger than those of the 

 inner layer. Distinct fibrillation of the cell-substance. (3) 

 In the ape the relations are precisely the same as in man. In 

 one instance I found amongst the inner layer of columnar cells 

 some that were goblet cells. (4) In the rabbit there is an 

 indication of an outer layer of cells only in the largest ducts, 

 but the cell-substance, especially in its outer part, is distinctly 

 fibrillated. (5) In the guinea-pig the interlobular ducts are 

 very conspicuous by their wavy long course, and by their 

 numerous branches. These latter often run side by side to- 

 gether for considerable distances. There is an indication of an 

 outer layer of cells only in the larger ducts, but the fibrillation 

 of the cell-substance is very marked. 



c. In the sublingual gland: — (1) In the dog the inter- 

 lobular ducts, especially in their larger branches, are lined with 

 a double layer of columnar cells. (2) In the rabbit the chief 

 ducts are lined with a double layer of columnar cells ; indication 

 of fibrillation of the cell-substance. (3) In the guinea-pig the 

 chief duct is lined with three layers of epithelial cells, an inner 

 layer of conical or short columnar cells, a middle one of spindle- 

 shaped cells, and an outer one of inverted conical cells. 

 Amongst the cells of the inner layer are numerous goblet cells. 

 The interlobular branches of the chief duct are lined with two 

 layers of short columnar cells. 



The intralobular ducts, or the salivary tubes of Pfliiger, as a 

 rule, are lined with a single layer of columnar cells, each with a 

 spherical or slightly oval nucleus in about the middle of the 

 cell, or even a little nearer to the inner than to the outer 

 boundary of the epithelium. The outer ])art of the cell-sub- 



