Section VIII. 



DISEASES OF THE PERITONEUM. 



1. Ascites. Hydrops ascites. 



Ascites is the term applied to the collection of serum-like 

 fluid in the peritoneum not due to an inflammatory process. 



Occurrence. Ascites occurs most commonh^ in the dog and 

 generally as a result of disease of the heart or liver. The disease 

 is seen in ruminants far more rarely, with the exception of the 

 general dropsy seen in cattle fed on products of sugar factories. 

 It is only quite exceptionally that the disease is observed in the 

 horse, pig and birds, and then it is generally a condition ac- 

 companying either chronic disease of the liver or the peri- 

 toneum. 



The disease was found in 1/0% of 70,000 dogs examined by Frohner. Cadiot 

 saw 37 cases in three years at Alfort. Out of 28 cases 10 were due to disease of 

 the heart and pericardium, 8 to tuberculosis, 4 to pleurisy, 2 to malignant growths 

 in the liver and lungs, 3 to chronic interstitial hepatitis and one to cancer of the 

 liver. 



Etiology. The principal cause of ascites unassociated with 

 general dropsy of the rest of the body and of the subcutaneous 

 tissue is congestion of the portal area. This congestion may be 

 due to compression of the portal vein by neoplasms, enlarged 

 h^nphatic glands or tumors of the pylorus or of the head of the 

 pancreas. Under these and other conditions there is thrombosis 

 of the portal vein. Portal congestion may also be set up liy 

 chronic diseases of the liver such as cirrhosis, echinococcosis, 

 and neoplasms. In these cases the interlobular branches of the 

 portal vein are subjected to pressure and the outflow of blood 

 from the portal area is thus obstructed. 



In cattle ascites is due most commonly to tuberculosis. Other 

 chronic diseases of the peritoneum, such as neoplasms, may have 

 a similar effect. These growths may cause obstruction of the 

 mesenteric or portal veins or of the great lymph vessels and 

 prevent the absorption of the lymph. The more common sequel 

 to these lesions is chronic peritonitis. 



As a part of general dropsy ascites occurs in cases of 

 thrombosis or compression of the posterior vena cava between 

 the liver and the heart, heart disease and chronic diseases of 



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