STRUCTURE OF THE KIDNEY. 349 



bonic acid, and other gases contained in jars, over mercury, 

 the volume of the gases became considerably diminished. 



The share which the evaporation from the skin has in the 

 maintenance of the uniform temperature of the body, and the 

 necessary adaptation thereto of the production of heat, have 

 been already mentioned (p. 195). 



CHAPTER XV. 



THE KIDNEYS AND THEIR SECRETION. 



Structure of the Kidney. 



THE kidney is covered on the outside by a rather tough 

 fibrous capsule, which is slightly attached by its inner surface 

 to the proper substance of the organ by means of very fine 

 fibres of areolar tissue and minute bloodvessels. From the 

 healthy kidney, therefore, it may be easily torn off without 



FIG. 120. 



Plan of a longitudinal section through the pelvis and substance of the right kid- 

 ney, i/; a, the cortical substance; b, b, broad part of the pyramids of Malpighi; c, c, 

 the divisions of the pelvis named calyces, laid open ; c', one of these unopened ; d, 

 summit of the pyramids or papillae projecting into calyces ; e, e, section of the narrow 

 part of two pyramids near the calyces ; p, pelvis or enlarged divisions of the ureter 

 within the kidney ; u, the ureter ; s, the sinus ; h, the hilus. 



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