3 I2 



PRACTICAL HISTOLOGY. 



[XXVIII. 



and the transition to the narrow part of the looped tubule of Henle. 

 This is perhaps easiest to obtain from a mouse's kidney. Isolated 

 straight tubules from the medullary part. To preserve this prepara- 

 tion, suck away the fluid and gently replace it with glycerine. 



Ureter and Bladder. Harden small pieces in Mtiller's fluid 

 (14 days) or in corrosive sublimate (5-6 hours), and then in 

 gradually increasing strengths of alcohol. Make transverse sections 

 of the one and vertical sections of the other. Flemming's fluid for 

 epithelium. Stain in haematoxylin and mount in balsam ; and 

 others in picro-carmine and mount in Farrant's solution. Or stain in 

 bulk in borax-cai-mine and cut in paraffin. The ureter of a cat or 

 monkey does very well, and it is well to use the contracted bladder 

 of a small mammal. 



9. T.S. Ureter (fig. 302). (a.) (L) Externally is a thin fibrous 



"Adventitia. 



FIG. 302. T.S. Lower Part of Human Ureter, e. Transitional epithelium ; s. Sub- 

 mucosa ; I and r. Longitudinal and circular smooth muscular fibres ; t. Tunica 

 propria. Miiller's fluid, x 15= 



coat or adventitia, consisting of connective tissue with the large 



vessels and nerves. 



(b.) The muscular coat consists of an outer layer of smooth 



muscle arranged circularly, and inside this a longitudinal coat 



arranged in bundles, the latter, of course, divided transversely. In 



the lower part of the ureter there is an incomplete longitudinal 



muscular coat outside the circular coat. 



(c.) The submucous coat is thin, and passes gradually into 



(d.) The mucous coat, which is thrown into ridges or folds, and 



is lined by transitional epithelium. 



