164 COLIC. 



Causation. This variety of colic is due to a number of somewhat 

 obscure causes. In a general sense we may say that anything which 

 increases intestinal peristalsis increases the risk of invagination. The 

 accident may follow intestinal congestion, but is most frequent in 

 animals suffering from intestinal worms, or in animals used for heavy 

 work. Under the influence of violent tractive efforts the peristaltic 

 movements are stimulated, and the intestine being in an oblique 



--%1^ 



Fig 



68. — Invagination of tlie intestine in an ox (the constricting portion has 

 been incised longitudinally). 



position on a plane inclined backwards, the contracted portion may slip 

 into the dilated section behind it. 



Invagination may also occur without any apparent cause, even in 

 animals standing in the stable. 



Symptoms. The attack always occurs suddenly, develops rapidly, 

 and is of an extremely grave character. 



Colic conies on while the animal is working, moving about, or resting, 

 according to circumstances, and at first resembles that due to congestion. 

 It afterwards becomes very violent ; the animals paw, stamp, show great 

 uneasiness, throw themselves violently down, and rise suddenly, only to 

 again lie down as before. The face expresses anxiety, suffering and 

 depression ; the tail is often kept lifted, and efforts are continually made 

 to deffecate, mucus being passed. By passing the hand into the rectum 

 the invagination may occasionally be discovered. 



