THE RENAL CAPSULES. 77 



extension, as manifested by it transmitting large calculi from 

 the kidney, and also, by its general enlargement in some cases 

 of obstructed urethra; its sensibility is exquisite when irritated 

 by a calculus passing down it. .</ 



Of the Renal Capsules. 



The Renal Capsules (Capsules Renales, Renes Succenturiati,) 

 are two small bodies, one on either side, placed upon the upper 

 end of the kidney. They are of a yellowish brown colour 

 tinged with red, have no excretory ducts, and are more dis- 

 tinctly developed and softer in the perfect foetus than in the 

 adult; whence they are ranked among those organs, as the thy- 

 mus gland, and others; which, having some peculiar value in 

 foetal existence, are perhaps unnecessary to that of the adult.* 

 They are of a triangular pyramidal shape, flattened before and 

 behind, and rest by a concave base upon the kidney; they are 

 about fifteen lines high and as many wide. 



They are surrounded by a proper coat of lamellated dense 

 cellular tissue, which, by detaching inwards its prolongations, 

 keeps the parts of these bodies together, and marks out their 

 divisions. In the centre of the renal capsule, a cavity may, 

 from time to time, be found; but, according to my own obser- 

 vations, nothing in our structure is less certain than its exist- 

 ence; and, in the opinion of Meckel, when found, it is the re- 

 sult of cadaverous decomposition. In the foetus it contains a 

 reddish viscid fluid, which seems to consist in a large share of 

 albumen, as it coagulates with alcohol; in children, this fluid 

 becomes yellow: in adults it is dark brown; and in old people 

 it is either entirely deficient, or in a remarkabJv small quan- 

 tity, 



Of the Minute Structure of the Capsufa Renales. The 

 arteries of these bodies come from the emulgents, from th.e 

 phrenics, and from the aorta. The veins of the right one termi- 

 nate in the cava ascendens, and of the left in the left emulgent. 



* This opinion has recently been confirmed in a dissection of a fcetus, where 

 J found the capsulsc reriajcs, though the kidneys were absent. 



8* 



