OF VETERINARY MEDICINE. 143 



PERITONITIS. 



Peritonitis is an inflammation of the peritoneum, the lining 

 membrane of the abdominal cavity. It covers the mesentery and 

 is reflected over the intestines. This serous membrane becomes 

 inflamed and the inflammation runs close to pleurisy. The stages 

 are the same. Two forms of peritonitis exist, acute and 

 chronic. The acute form runs its course in about 10 days, the 

 chronic may run along for months. 



Etiology. — The most common cause is traumatism with in- 

 fection. External violence, kicks from other horses for in- 

 stance, especially those severe enough to produce ventral hernia ; 

 exposure to cold and dampness ; strongylus armatus ; starvation ; 

 old age (no appreciable cause known), — these are the main 

 causes of peritonitis. In the third stage of peritonitis the effu- 

 sion accumulates in the abdominal cavity and this condition is 

 called ascites. Ascites may be due to chronic kidney and liver 

 diseases without peritonitis, it being a dropsy from obstruction 

 of the portal circulation or from defective secretion of the urine. 

 It is sometimes tuberculous in cattle, and often follows castra- 

 tions and abdominal operations. 



Semeiology. — Pain is severe but the animal is comparatively 

 quiet. Motion aggravates the pain so that instead of rolling and 

 tossing and kicking, the horse is quiet. His back is more or less 

 arched; abdominal muscles fixed; pulse and temperature up, 

 temperature about 104, pulse 60-100; pulse hard and small; pres- 

 sure upon the belly causes pain. In the third stage the exudate 

 is profuse. This is difficult to recognize as the distension of the 

 belly is not marked. The legs swell ; dropsical enlargement under 

 the belly is usually seen but not always. The mucous mem- 

 branes are first injected and later get pale; emaciation is rapid. 

 The prognosis is usually unfavorable when the disease is exten- 

 sive enough to be appreciable. 



Post Mortem. — Fatal cases of peritonitis have ascites so that 

 the post mortem will show much serum in the abdominal cavity. 

 This varies in color from amber to red, depending upon the 

 acuteness of the attack. The peritoneum is generally red over 

 most of the surface, is softened and easily torn or punctured. 



