STKUCTUEE OF THE KIDNEY. 



19f) 



in the different parts of a tubule. In the capsule the epithelium is 

 flattened and is reflected over the glomerulus (fig. 228, a). In the first 

 convoluted and spiral tubules it is thick, and the cells show a marked 



FIG. 228. TUBULES FROM A SECTION OP THE DOG'S KIDNEY. (Klein.) 



, capsule, inclosing the glomerulus; n, neck of the capsule; c, c, convoluted tubules; b, 

 irregular tubules ; d, collecting tube ; e, e, spiral tubes ; /, part of the ascending limb of 

 Henle's loop, here (in the medullary ray) narrow. 



fibrillar structure (figs. 229, 230). Moreover, they interlock laterally 

 and are difficult of isolation ; in some animals they have been described 



FIG. 229. STRUCTURE OP THE EPITHELIUM OP THE CONVOLUTED TUBULES. 

 (Heidenhain.) 



<l, section of a convoluted tubule from the rat, showing the unaltered protoplasm occupying 

 a circular area around the nucleus of each cell ; a, 6, c, isolated cells from the convoluted 

 tubules of the rat ; e, isolated cells from the dog's kidney, viewed from the inner surface, 

 and showing the irregular contour of the protoplasm ; /, isolated cells from the newt, 

 showing the rods and a homogeneous cuticular layer. 



