308 THE MANAGEMENT AND DISEASES OF THE DOG. 



dogs, and is usually associated with some old-standing dis- 

 ease, either connected with the heart or large venous trunks, 

 in which some obstruction to the proper return of blood is 

 present, often originating in some morbid condition of the 

 liver, spleen, lungs, or kidneys. In the dog it is never the 

 result of chronic peritoneal inflammation. 



" Active and passive dropsy," Watson observes, " resem- 

 ble each other in the result ; namely, in the collection of 

 serous liquid in the circumscribed cavities and vacuities of 

 the body. They differ in the rate at which the collection 

 augments. 



" In the well-marked acute dropsies, the liquid is rapidly 

 effused in quantity much beyond the natural amount of ex- 

 halation. In the well-marked passive dropsies the exhalation 

 goes on as usual, but the fluid exhaled iS not taken back again 

 into the circulating vessels with sufficient facility. In one 

 case the circulation is disturbed and tumultuous ; in the other 

 it remains tranquil. 



" Although all dropsical transudations probably take place 

 through the walls of the capillary vessels, there ~would seem 

 to be, in the more acute forms of dropsy, an increased flow of 

 blood in the arterial channels ; while in the completely chron- 

 ic forms there is a defect of absorption by the veins. Active 

 dropsies are sometimes spoken of as belonging to the left side 

 of the heart, passive dropsies to the right. 



" What connects all these forms of dropsy is a preter- 

 natural fulness in some part, or the whole of the hydraulic 

 machine. And this seems to be the grand key to the entire 

 pathology, as well as to the remedial management, of the dis- 

 ease."; ' 



Symptoms.— T]\& first symptom generally observed is an 

 enlargement of the abdomen, but as this may arise from, 

 causes other than ascites — to wit, pregnancy tumors, obesity 

 or ovarian dropsy — it is necessary to obtain, by examination, 

 more confirmatory evidence. The above-mentioned writer 

 remarks : 



