THIRST, a craving for water or other drink. As appetite shows a need for the intro duction of food into the system, so thirst is a sensation indicating the necessity of an in creased supply of water. This sensation is referred to the throat, yet it is not a purely local feeling, but an index of the wants of the tissues at large, for thirst cannot be allayed unless the water swallowed reaches the stom ach, is absorbed and carried into the blood. Thirst may also tie relieved by the direct intro duction of water into blood-vessels or by rectal injections of it, or by its absorption through the skin. How long the demands of thirst may be successfully withstood cannot be stated defi nitely, since human beings as well as the lower animals differ among themselves, and under varying circumstances of climate, etc., as to the degree of tolerance. Certain it is that of all substances a regular supply of water is most essential to the maintenance of life. If de prived of it for even 8 or 10 hours, greater in convenience, pain and debility are suffered by an individual than from an equal deprivation of solid food. As thirst is but the expression of a dearth of water in the tissues, any condition which causes a more rapid elimination of water than usual will increase thirst. Such is the
effect of severe muscular exercise, especially, for example, the exertion in a heated atmos nhere habitual with stokers, iron-puddlers, etc. Thirst is also increased by certain articles of food, excess of salt or sugar, for example: in febrile disorders; in severe diarrhoms and himorrhages; in diabetes; in acute gastritis; in polyuria; in certain forms of hystena, etc.
For allaying thirst nothing is so .grateful as pure cool water, sipped a little at a time. Sweet drinks are not as effective in relieving thirst; but the vegetable acids in oranges, lemons, grapes, limes, etc., have a tendency to allay thirst, and to lessen the desire for large quan tities of fluid, since the acid provokes an in creased flow of saliva. Toast-water, small pieces of ice, effervescent drinks and dilute phosphoric acid alone or combined with a little aromatic bitter are also of value. In fever, cleansing the mouth, and swabbing it with glycerine, borax and water is of more service sometimes than drinlcing large quantities of water.