Considered in a dietetical point of view, water serves three important purposes in the animal economy ; namely, it repairs the loss of the aqueous part of the blood, caused by the action of the secreting and exhaling organs ; secondly, it is a solvent of various alimentary substances, and therefore assists the stomach in the act of digestion, though, if taken in very large quantities, it may have an opposite effect, by diluting the gastric juice ; thirdly, it is a nutritive agent, that is, it assists in the

formation of the solid parts of the body. As a diluent, water is indispensable to the preservation of health. The body being composed of solids and fluids, there must be maintained a certain relative proportion of these, to constitute that state of system called health. In a full grown adult, the solid matter of the body, by which we mean all that substantial part of the frame

which is not in constant motion in the vessels, amounts to only about one fifth of the weight of the body --Chaussier says, one ninth of the total weight, the difference,

perhaps, being- owing to the fact that there is a quantity of fluid combined with the solids in so intimate a manner, as almost to constitute a part of their substance. The diminution of the fluid part of the body, is the cause of an uneasy sensation, indicating the necessity of repairing the waste of fluids, which we familiarly call

thirst. This is a sensation connected with some natural state of the corporeal funo tions, and altogether independent of the occasional excitement of foreign bodies, although it may be induced by these. There is a demand for a certain supply of liquid which is the result of repletion of the stomach, and the cause of our drinking