OF VETERINARY MEDICINE. 129 



COLIC. 



Colic in the abstract, of course, relates to the colon; but as 

 a disease we apply the word to peculiar abdominal pain. Colic 

 is divided into two classes, spasmodic and flatulent. 



Spasmodic colic is a painful affection of the bowels without 

 fever or inflammation. The pain is intermittent and is pro- 

 duced by irritation of the mucous lining of the bowels. This ir- 

 ritation extends to the muscular coat, which contracts spasmod- 

 ically through the stimulation of the sympathetic nerves. This 

 contraction is usually violent and painful. It is the effort of 

 nature to increase peristalsis to push the irritant along. If 

 nature is successful in doing this, the trouble ends; but if not, 

 then the action is repeated. Therefore the pain is intermittent. 

 If nature fails entirely, the irritation will later produce conges- 

 tion and inflammation, and eventually death by enteritis. 



In such a case the spasms increase in violence as the case 

 runs along. In a favorable case they may stop altogether, but if 

 they do recur, it is with decreased violence until they stop. 



Etiology. — As to the causes of colic, first comes errors in diet, 

 producing indigestion. This covers overeating, poor food, heavy 

 drinking soon after eating, frozen food,, — this chills the mucous 

 lining and the reaction from the chill is accompanied by cran:ps, 

 eating when physically exhausted, drinking large draughts of cold 

 water especially when warm, and still more so if the horse is 

 tired, intestinal concretions, — usually the calcareous ones (a cal- 

 culus in the bowel does not cause pain until it rolls out of its 

 pocket, then it acts as an irritant, but the pocket in which it 

 grows has become accustomed to its weight gradually), para- 

 sites such as ascarides, strongylus armatus and strongylus tctra- 

 canthus. Of these three worms the last two mentioned are more 

 likely to produce colic, the first to produce diarrhoea. The young 

 embryos of these worms sometimes work their way into the colic 

 artery, start a colony and eventually cause an aneurism, which is 

 more or less obstructed by worms. Any alteration or disturbance 

 of the circulation in the bowels produces violent pain the same as 

 congestion in pleurisy causes pain. This pressure in the colic 

 artery produces pain sufficiently to ultimately kill the animal. 



