588 DISEASES OF THE PERITONEUM. 



some otlicr situations, these acting often mcclianically by 

 pressure upon large or small venous trunks. I have also 

 observed that aged mares which have had several foals are 

 rather liable to suffer from ascites, probably from repeated 

 pressure of the gravid uterus upon the great abdominal veins. 



h. Anatomical Characters. — In a few cases where the pre- 

 sence of the fluid seems unconnected with any actively existing 

 disease, there may, apart from the dropsy, be nothing abnormal. 

 A greater number will show, as the sole lesion in any way 

 associated with the ascites, a thickening, more or less extensive, 

 of the peritoneal membrane. This latter state is usually quite 

 distinctive in those cases of subacute peritonitis which have 

 been mentioned as happening in young animals which have 

 been exposed and otherwise indifferently treated. Most fre- 

 quently, however, several organs give unmistakable evidence 

 of disease and varying structural change. 



The peritoneum may exhibit traces of active and recent in- 

 flammatory action; the liver or spleen may be enlarged, 

 atrophied, or otherwise texturally changed ; morbid growths 

 may be connected with these organs or scattered over the 

 membrane, free or attached ; or the heart may exhibit hyper- 

 trophy with dilatation of its cavities and weakening of its 

 walls, or other changes in some way obstructing the general 

 circulation. 



The quantity of fluid in the cavity is occasionally very large, 

 amounting to many gallons ; it is usually entirely serous, of a 

 straw or greenish colour ; in some particular instances it will 

 contain shreds of lymph. 



Symptoms. — When unassociated with some diseased condi- 

 tion more pronounced in character, the indications of ascites 

 are usually occult, insidious in development, and sometimes 

 spread over a considerable period of time. At first there may 

 be little attractive and certainly nothing diagnostic. The 

 animal is dull and spiritless, and if in the field there is a desire 

 to be alone ; appetite impaired, general aspect unthrifty, with 

 indications of a badly nourished body. Watched more care- 

 fully, or examined more minutely, we may notice that it is dis- 

 posed to rest much, not, however, with comfort ; the hair is 

 overgrown, and the abdomen becomes gradually pendulous. 

 The pulse is weak and rather frequent, with, in some cases, a 



