196 PRACTICAL HISTOLOGY [XXV 



rays (cp. 6) ; in the outer part of the layer, rather 

 large arteries arid veins cut transversely or obliquely 

 will be seen (cp. 1). 



7. In the cortex : 



The capsules, with the nuclei of their epithelium. 



The glomerulus in each capsule (cp. 6) and the 

 nuclei of its capsular covering and of its capillaries. 



The narrow neck of the capsule may perhaps be 

 seen in some capsules in which the section has passed 

 longitudinally through the neck. 



The coiled course of the convoluted tubes; the 

 outlines of the individual cells may or may not be 

 distinct, each has a spherical nucleus and is striated 

 in its outer portion. Sometimes the lumen is large, 

 sometimes it can scarcely be made out. 



In the medullary rays, the collecting tubes and 

 ascending and descending limbs of loops of Henle. 



The basement membrane distinct in all portions of 

 the urinary tubule. 



In the cortex are deeply stained short tubules running out 

 from the rays and sometimes seen to be continuous with the 

 ascending loops of Henle ; their cells resemble those of the 

 ascending loop except that they are of unequal size, thus giving 

 a very zigzag outline to the tubule; this is the ' irregular ' 

 portion of the urinary tubule. 



3. Sections at right angles to the collecting tubes 

 (a) through the cortex, (b) through the intermediate 

 layer, (c) through a papilla. (Mercuric chloride; hasma- 

 toxylin.) Mount together. 



Note in (a) the medullary rays entirely surrounded 

 by convoluted tubes and glomeruli, in (b) the groups of 



