THE KIDNEY. 



2. The "markings of the cortex." These consist of alternat- 

 ing light and dark lines, radiating from the bases of the Malpighian 

 pyramids. The lighter masses consist largely of collecting tubes, 

 together with ascending limbs of Henle's looped tubes otherwise 

 called medullary radii. Between these lighter areas the dark 

 labyrinths appear ; in which, by careful attention, the Malpighian 

 bodies may be made out as minute red dots. 



3. A region just outside the medullary pyramids not as well 

 marked as the outer cortex, in which few Malpighian bodies present 

 the boundary region. 



4. The finely striated medullary or Malpighian pyramids. (The 

 section will usually include portions of two of the last.) 



5. That the bases of the pyramids do not appear as a sharply 

 defined line, but fade into the boundary region ; while the union of 

 the latter with the cortex proper is equally ill-defined. 



(L.) Fig. 88. 



1. The cortical labyrinths, in which search for : 



(a) Portions of the interlobular arteries, together with the 

 smaller twigs of the arterial arcade. 



(b) The Malpighian bodies. (The tuft or glomerulus which, 

 with this power, appears as a granular mass, is wanting in numerous 

 places as indicated by the empty capsules.) 



(c) The remaining area occupied largely by the convoluted 

 tubes, proximal and distal. 



2, The pyramids of Ferrein. (Observe that, as they pass into 

 the pyramids of Malpighii, they are well defined, but that they are 

 lost as they approach the region of the capsule of the organ.) 



(H.) Fig. 89. 



1. A Malpighian body. (Select, after searching several fields, 

 a specimen which shows either the afferent or efferent vessel of 

 the glomerulus. It will be very difficult to find a capsule con- 

 nected with the neck of a proximal convoluted tube, as they 

 rarely happen to be so sectioned. You may indeed be obliged to ex- 

 amine a dozen slides before you succeed. ) Note 



(a) The capsule (of Bowman or of Muller). (Observe its thick- 

 ness ; as this becomes important in connection with the pathology of 

 the kidney.) 



(b) The flattened cells, lining the capsule. (Many of them 

 will have become detached hTthe preparation of the section.) 



(c) The glomerulus. (The great number of nuclei obscures the 

 loops of capillaries. Kemember that the nuclei belong partly to the. 



