THE KIDNEY 189 



vessels and partly to the flattened cells covering the glomerulus. 

 Endeavor to find transversely divided loops of the vessels, show- 

 ing blood within.) 



d. That the glomerulus does not entirely fill the capsule. 



e. That the glomerulus is frequently divided. 



/. That the glomerulus is usually in contact with the capsule 

 at some one point, where search may be made for 



y. The afferent and efferent arterioles. (The afferent is more 

 frequently demonstrable, and may be differentiated by its large 

 size, and the connection, which can often be traced, with the inter- 

 lobular artery.) 



2. Convoluted tubules. (The convoluted tubules found just 

 beneath the capsule of the kidney generally belong to the distal 

 variety, and they are not as favorable specimens as the deeper 

 proximal portions, on account of the crowding of the tubular ele- 

 ments in the outer cortical regions. Select a transverse section 

 and observe : ) 



a. The thin membrana propria, or wall of the tube. (It does 

 not appear to be made up of fibrillated connective tissue, but .has 

 a rather homogeneous structure. Nuclei, however > may occasionally 

 be seen, which apparently belong to this tissue.) 



1). The peculiar lining cells. (They are unlike any other 

 parenchymatous elements found in the body. Note that, while 

 they are evidently of the columnar or cylindrical type, they differ 

 greatly in form and size. The protoplasm is hazy, granular, and 

 frequently striated. They take a dirty brick -red hue from the 

 eosin.) 



c. The lumen. (Compared with the diameter of the tube- wall, 

 the lumen is very small, and presents a stellate figure. The urine, 

 in passing through the tubule, is, consequently, brought in contact 

 with a very considerable portion of the lining. ) 



3. The large proportion of the cortical area occupied by the 

 convoluted tubules, and the exceedingly small amount of inter- 

 tubular connective tissue. 



4. The intertubular capillaries. (These are exceedingly small 

 and difficult of demonstration unless filled with blood. The nuclei 

 of the endothelial wall are frequently seen. The cells of the con- 

 voluted tubules are not infrequently detached from the membrana 

 propria, and the space so formed may be mistaken by the careless 

 observer for longitudinal sections of capillaries. These vessels are 

 much better seen in an injected kidney; although if ,an organ be 



