Excretion. 55 



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 through- 

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

 the membrane is delicate and easily injured. A cruel 

 practice followed by some grooms is known as "figging" 

 and consists of the introduction of irritants (usually gin- 

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

 to a slow, slouchy animal or to excite him so that any 

 lameness 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 per- 

 form this useful work. The kidneys are two glands sit- 

 uated to the right and left under-sides of the spinal col- 

 umn, 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 depres- 

 sion or spot called the hilus; these vessels, nerves, con- 

 nective tissue and urinary tubes (tubuli uriniferi) go to 

 make up the kidney substance which is enclosed by a 

 fibrous covering. The small tubes wind a great deal 

 and empty into a cavity know as the sinus, which is a 



