General Discases. 329 
“Tf water be injected in some quantity into the blood- 
vessels of a living animal, the animal soon perishes—dying 
generally by coma, or by suffocation ; and when the carcass 
is examined the lungs are found to be charged with serous 
liquid ; or water is discovered in the areolar tissue of some 
other part, or in the shut serous membrane. _If,. however, 
the animal be first bled and then a quantity of water 
injected equal to the quantity of blood abstracted, the 
injection is followed by no serious consequences. 
“ Facts like these throw, as it seems to me, a strong light 
eon aconfessedly obscure part of pathology. It appears 
that under various circumstances the blood-vessels may 
receive a considerable and unwonted accession of watery 
fluid, and that they are very prone to get rid of the redund- 
ance. When they empty themselves through some free 
surface, their preternatural distention is relieved by a flux. 
If, on the other hand, the surface be that of a shut sac, in ° 
discharging their superfluity they cause a dropsy. Why 
sometimes this organ and sometimes that is selected as the 
channel by which the superabundant water shall be thrown 
out of the vessels, we can seldom tell.” 
Chronic or Passive Ascites is more commonly seen in old 
dogs, and is usually associated with some old-standing 
disease, 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 condi- 
tion of the liver, spleen, lungs, or kidneys. In the dog itis 
never the result of chronic peritoneal inflammation. 
“ Active and passive dropsy,” Watson observes, “resemble 
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 
exhalation. In the well-marked passive dropsies the ex- 
