326 



THE GENITOURINARY ORGANS. 



is here followed. In the epithelial cells of the proximal convoluted 

 portion there may be recognized an outer or basal portion of the 

 cells, in which there is found a spongioplastic network with rectan- 

 gular meshes, with cytoreticular fibrils running parallel and at 

 right angles to the basement membrane. In the meshes of this 

 network there is found hyaloplasm. The cytoreticular fibrils which 

 are at right angles to the basement membrane contain numerous 

 granules, giving the basal portions of the cells a striated appear- 

 ance. The inner portions of the cells contain a cytoreticulum and 

 hyaloplasm ; the reticular fibrils do not, how r ever, contain granules, 



Fig. 262. From section of cortical . substance of human kidney; X 240: a, Epi- 

 thelium of Bowman's capsule; t>and.i/, membrana propria ; c, glomerular epithelium; 



f, blood-vessels ; /, lube of the "lomerulus ; ^, commencement of uriniferous tubule ; 

 A,~eplthelium~bf the neck ; i, epithelium of proximal convoluted tubule. 



the inner portions of the cells presenting, therefore, a much less 

 striated appearance than the outer portions. In tissues not well 

 fixed there is often observed in the cells a free border which presents 

 the appearance of being made of stiff fibrils or coarse and short 

 cilia, which has been interpreted as a distinctive structure. Such a 

 striated border is in all probability a result of partial disintegration 

 or maceration of the cells. The nucleus of these cells is of nearly 

 spheric shape and is situated in the inner part of the basal portions 

 of the cells. The cells, especially in their inner non-striated regions, 

 are so intimately connected that the cell limits are not always dis- 

 tinguishable. In the guinea-pig the basal regions of the lateral 



