328 The Management and Diseases of the Dog. 
“ Now it is well ascertained that when the excretion of 
aqueous fluid of one such surface is checked, the exhalation 
from some other surface becomes more copious. 
“It is probable that the aggregate quantity of water thus 
‘ expelled from the system in a given time, cannot vary 
much, in either direction, without deranging the whole 
economy. But we are sure that the amount furnished by 
any excreting surface may vary and oscillate within certain 
limits consistent with health, provided that the defect or 
excess be compensated by an increase or diminution of the 
ordinary expenditure of watery liquid through some other 
channel. Sound health admits and requires this shifting 
and counterpoise of work between the organs destined to 
remove aqueous fluid from the body. This. supplemental 
or compensating relation is more conspicuous in regard to 
some parts than to others. The reciprocal but inverse 
accommodation of function that subsists between the skin 
and the kidneys affords the strongest and the most familiar 
example. ; 
“In the warm weather of summer, when the perspiration 
is abundant, the urine is proportionately concentrated and 
scanty. On the other hand, during winter, when the 
cutaneous transpiration is checked by the agency of 
external cold, the flow of dilute water from the kidneys is 
strikingly augmented.* All this is well known to be com 
patible with the maintenance of the most perfect health. 
But supposing the exhalation from one of these surfaces to 
be much diminished, or to cease, without a corresponding 
increase of function in the exterior, then dropsy, in some 
form or degree, is very apt to arise. The aqueous: liquid 
thus detained in the blood-vessels seeks, and at length 
finds, some unnatural and inward vent, and is poured forth 
into the areolar tissue, or into the cavities bounded by the 
serous membranes. 
* This is especially noticeable after bathing. 
