THE URETERS. 235 



cut surface. A fter a minute and a half the silver solution 

 is rinsed off with distilled water, and the piece of kidney 

 is placed in a beaker of strong spirit, with the silvered 

 surface exposed to the sunlight. When brown it may be 

 removed from the light, but is left in the spirit for twenty- 

 four hours; one or two sections are then made from the 

 brown surface, clarified in oil of cloves, and mounted in 

 dammar. 



THE SUPRARENAL CAPSULE. 



Preparation 11. To prepare the suprarenal cap- 

 sule it is separated from the surrounding fat, divided 

 into two or three pieces by transverse cuts, and placed 

 in two per cent, of bichromate of potash solution for 

 fourteen days, when the hardening may be completed 

 in spirit in the usual manner. Hardening the organ 

 in spirit alone also gives very good results. The 

 mode of preparing the sections, which should include 

 both cortical and medullary substance, calls for no 

 special description. 



If the human suprarenal is not obtainable in a 

 fresh condition (the medullary substance very readily 

 softens and breaks down after death), that of the 

 guinea-pig, which is large comparatively to the 

 size of the animal, and has the distinction between 

 cortical and medullary substance well marked, may 

 advantageously be employed. 



Preparation 12. In a teased-out preparation of 

 the fresh organ the cellular elements of the cortical 

 and medullary substance may respectively be studied, 

 and the effect of a solution of yellow chromate of 

 potash in coloring the medullary cells brown may 

 be observed. 



THE URETERS. 



Preparation 13. The ureters are prepared in 

 the same way as the intestine by moderately dis- 

 tending an excised portion with a mixture of equal 

 parts of spirit arid | per cent, chromic acid solution, 



