THE ACTION OF DIURETICS. 
347 
In a word, the absorbed water augments the quantity of serum of 
the blood, and alters the assimilable ingredients of the liquid, and 
may in the long run even attack the globules themselves, and so 
produce a veritable cachectic condition. Here, then, comes the 
reason why the system, in its admirable economy, rids itself as 
actively as possible, through the medium of the kidneys, of this 
excess of liquid, so as not to suffer itself to be harmed or emaciated 
through it, as in cachexia, when its proportion becomes continually 
augmented for a lapse of time, and when the debilitated organs can 
no longer suffer its expulsion, or when the discharges are not in 
ratio with the supplies. 
So that, on the whole, the water taken in with the drink is in- 
tended to quench the thirst by maintaining the aqueous part of the 
humours in just proportion. The part which exceeds the want of 
the economy is cast out, either through the kidneys or through the 
skin. The quantity expelled in the form of urine is always in an 
inverse ratio with that exhaled by transpiration, and both serve as 
a vehicle for those fixed principles which are intended to be thrown 
off by the two passages of depuratory secretion. 
Mucilage, which seems to be nothing more than a gummy prin- 
ciple combined with water and some saline matters, is likewise a 
pretty certain diuretic : given in large proportion in drinks, this 
principle is neither digested nor absorbed, and passes out through 
the alimentary passages scarcely altered, producing a relaxing 
effect. Less concentrated mucilaginous drinks are absorbed by the 
mesenteric veins, and the gummy principle is carried into the blood. 
If it exists in small quantity, it is attacked by pulmonary combus- 
tion as a mutual principle, unazotized, of vegetable origin, serving 
to keep up animal heat. In the case in which it exists in great pro- 
portion, it is not entirely consumed in the circulatory passages, but 
quits the system nearly in its natural state through the urinary 
canals. In fact, experience shews that, under the influence of 
mucilaginous drinks, the urine becomes thick, ropy, soft to the 
feel, and flows in abundance, gliding smoothly along the genito- 
urinary mucous lining ; thus it is that this, well enough known to 
practitioners, is frequently introduced into practice in irritable 
affections of the urinary apparatus. 
To what should we ascribe the diuretic effect of mucilage? — to 
the large quantity of water it contains, or to the alkaline and cal- 
careous salts in it in pretty considerable proportion 1 Probably to 
both. In regard to the water, the question does not admit of a 
doubt; and as to the salts, they contain about a tenth in weight 
of the mucilage of linseed, and are, perhaps, in larger proportion 
still in that of plants called nitrous, as borage and pellitory : and 
if, on the other hand, we take into account the extreme state of 
division in which these salts are found, we could hardly refuse to 
