216 MANUAL OF HISTOLOGY. 



the stroma is a colorless, transparent substance, which, after 

 immersion for a variable time in a solution of chromate of po- 

 tassa or ammonia, resolves itself into a thin fibrous reticulum, 

 containing at regular intervals round or elliptical nuclei; 1 

 these, according to Schweigger-Seidel, belong to stellate or 

 spindle-shaped corpuscles, which may be isolated by macera- 

 tion in hydrochloric acid. The nuclei are only seen in the 

 lower portion of the medulla ; the fibrous appearance of the 

 stroma is retained some distance beyond this point. 



The nerves follow the course of the arteries of the kidney 

 and seem to supply only those vessels. 



The lymphatics at the hilum are derived from the interior 

 of the organ, and from a network of small lymph-branches 

 situated between the bundles of fibres of the capsule. The 

 latter communicate with lymph-canals in the interior of the 

 organ.* 



The capsule of the kidney is a fibrous tissue, containing 

 some few elastic filaments. It is divisible into two layers, an 

 outer and an inner one. The former, about 0.1 to 0.2 mm. in 

 thickness is continuous with the connective tissue which sur- 

 rounds the blood-vessels at the hilum ; the latter, about 0.025 

 mm. in thickness, terminates at the points where the papillae 

 enter the calices. Immediately underneath the inner layer, is 

 a large meshed reticulum of smooth muscle-fibres, 3 some of 

 which traverse the substance of the gland for a short distance. 



The calyx, at its junction with the papilla, is covered with 

 epithelium, which is continued on to the apex of the papilla ; 

 it contains, in addition, muscle-fibres disposed at right angles 

 to one another, and connective tissue. 



Natural injection of the tubules of the Tcidney by the 

 sulphindifjate of soda.* The first to inject the kidney in this 

 way was Chronsczewski ; 6 but his experiments were not very 

 successful, at least so far as the kidney was concerned. Those 

 of Heidenhain ' which have been confirmed by the writer, 7 give 



1 Henle : loc. cit. 8 Ludwig, in Strieker's Manual. 



* Eberth : Med. Centralbl., No. 15, 1872. 



4 Commonly known in the laboratory and in commerce as indigo-carmine. 



5 Chronsczewski, in Virchow's Archiv, Bd. XXXI., p. 187; also Bd. XXXV., p. 

 158. 



Max Schultze's Archiv, Bd. X., p. 1, and Pfluger's Archiv, Bd. IX., p. 1. 

 1 Mayer : Histol. of Kidney. Prize dissert. , 1876. 



