THE KIDNEYS AND URETERS. 119 



-In structure they are composed of two different looking 

 substances which have heen called cortical and medullary. 

 The first is yellowish and external, and appears to be striated 

 perpendicularly to its surface, from the direction in which / the 

 capillaries run through it. The medullary is in the centre, and 

 is brown colored and soft. 



Of the Kidneys and Ureters. 



The kidneys are two glandular bodies which secrete the 

 urine. They are of a dull red color, and their form has a 

 strong resemblance to that of the bean which bears their 

 name. They have a peculiar texture, which is uniform, and 

 not granulated or composed of acini ; and they are covered 

 by a thin delicate fibrous tunic, which has no connection with the 

 peritoneum. 



They are situated in the lumbar regions of the abdomen, one 

 on each side of the spine. They are opposite to the two last 

 dorsal and the two first lumbar vertebra?. They rest principally 

 upon the psoas and quadratus lumborum muscles, and their 

 position is oblique ; the concave edge presenting inwards and 

 forwards, the convex edge backwards, and the upper extremity 

 approaching nearer to the spine than the lower. 



The Right Kidney is situated rather lower than the left: 

 it is below the posterior part of the right lobe of the liver, and 

 behind the duodenum and the colon. The Left Kidney is 

 below the spleen, and behind the descending portion of the 

 colon. Each of the kidneys is below and very near lo one of 

 the glandulae renales. 



They are surrounded with a large quantity of lax adipose 

 membrane, which in corpulent persons forms a very large mass 

 of adeps around them ; while in the emaciated they are sur- 

 rounded with a membrane almost free from fat. Each kidney 

 has two broad sides, two extremities, and two edges. The side 

 or surface which is posterior, when the kidney is in its natural 

 situation, is rather broader than the other. The upper extre- 

 mity, or portion, is also broader and larger than the lower. The 

 edge which is posterior and external is regularly convex ; the 

 anterior edge is concave ; but the concave edge or margin is 



