Excretion. 61 



operation in which the muscles that pull the tail down 

 have been cut. 



The rectum is largely used by veterinarians as an organ 

 by which certain medication (injection, etc.) can be 

 performed upon the animal, feeding is rarely attempted 

 in animals by this means ; it must, however, be remem- 

 bered that the mucous membrane extends throughout 

 the digestive tract as far as the anus, and also that the 

 membrane is delicate and easily injured. A cruel prac- 

 tice followed by some grooms is known as "figging" and 

 consists of the introduction of irritants (usually ginger) 

 into the rectum; the object being to give a false life to a 

 slow, slouchy animal or to excite him so that any lame- 

 ness is hidden, or to render the horse so irritable as to 

 prevent a fair examination. 



B. The Urine. The consideration of the second method 

 of excretion calls for a description of the organs the 

 kidneys, ureters, bladder and urethra which perform 

 this useful work. The kidneys are two glands situated to 

 the right and left under-sides of the spinal column, the 

 right kidney being situated just behind the last ribs, the 

 left one being a couple of inches further back. In the 

 horse they are heart or bean shaped, in cattle and sheep 

 each one is somewhat divided into a grapelike mass. In 

 front of the kidneys and attached to them are two glands 

 (suprarenals) whose function is unknown, unless they 

 perform work during the period before birth. Blood 

 vessels and nerves enter the kidney at a depression or 

 spot called the hilus; these vessels, nerves, connective 

 tissue and urinary tubes (tubuli uriniferi ) go to make up 

 the kidney substance which is enclosed by a fibrous cov- 



