304 LIQUIDS. 



hence it is not good for drinking purposes, unless it be thoroughly 

 filtered before being used. 



RIVER-WATER is partly rain-water and partly spring-water, 

 subject to impurity from the soil and from decaying vegetable and 

 animal matters, and therefore only usefu] to a limited extent. The 

 flow of the stream and the absorbing influence of vegetation tend 

 to purify the water by oxydation. 



DISTILLED WATER is pure, but insipid from its lack of air; its 

 softness makes it easily susceptible to the action of lead ; but it is 

 excellent for making tea or other infusions. 



Water may be impure from an excess of saline ingredients, 

 from the presence of organic impurities, or from contamination 

 with lead. The chief danger to health is from organic impurity. 

 Cholera and typhoid fever have been traced to drinking impure 

 water. Lead contaminates pure water, but if there be a moderate 

 quantity of earthy salts in the water they form an insoluble 

 incrustation in the pipes, which is protective. 



It is most important that the receptacles for water tanks 

 and cisterns should be carefully examined and thoroughly cleansed 

 at regular seasons, especially after a time of drought and before 

 the approach of winter. Much mischief is often done and disease 

 induced by allowing cisterns to fill up after they have been dry or 

 the water in them Tow; the quantity of sediment and filth is fre- 

 quently very great and if not carefully removed becomes mingled 

 with every fresh influx of water, and thus diphtheria, typhoid fever 

 and other blood diseases may be set up. The deleterious conse- 

 quences that ensue from neglect of this duty are often alarming, 

 although the source of the evil be unsuspected. Boiling water 

 removes some of the salts from hard water, and destroys the activity 

 of any organic impurities. Filtration, especially through charcoal, 

 also purifies the water by removing organic matters, but it is not to 

 be relied upon. The filter must be frequently cleansed. 



Water may be administered to patients at any temperature that 

 may be desired, but if very cold the quantity should be very small, 

 for in some diseases it is undesirable to lower the temperature of the 

 internal organs. If the stomach is in such an irritable state that no 

 liquid can be tolerated, the thirst may be partially allayed by suck- 

 ing small pieces of ice; but where ice is substituted for water its 

 use must be constant, because ice tends to increase thirst rather than 

 allay it; hence the desire for drink is imperfectly satisfied, so that 

 where water can be borne ice should not be given. Moreover, the 

 reactionary effects of its continued use are not beneficial. When 

 ice cannot be procured, water may be cooled in a porous water-jar. 

 Ice is a valuable medical agent, and is now extensively used both 

 internally and externally, chiefly to check hemorrhage, to moderate 

 inflammation, and to soothe uneasy sensations in febrile and other 

 disorders. In inflammation of the brain or its membranes, and in 

 the severe headache of the early stages of acute fevers, it is most 



