WATER. 



mere quenching of thirft, though this is in itfelf highly ad- 

 »anta"-eous ; but it is after fo much Uquid is added to the 

 circulating mafs, that the truly diluent effefts are pro- 

 duced. Thefe confift, in Dr. S.'s opinion, in diminifhing 

 the morbid heat and violence of reaftion in the folids ; in pre- 

 ferving all the fecvetory organs in a pervious ftate ; and in 

 checking that tendency to fpontaneous change, which ren- 

 ders the fluids pofitively noxious to the vefTels in which they 

 are contained, and unfit to perform thofe funftions, on which 

 the health of the body fo effentially depends. 



It appears poffible, however, in the opinion of the fame 

 author, to carry dilution in aftive fever to excefs. In 

 fever, as is well known, the exhalent vefTels are compara- 

 tively inaftive, or morbidly conftrifted, and the fecretion of 

 urine is defeftive in quantity. In fuch cafes, it is often 

 better to take liquids in fmall divided dofes, which has the 

 effeft of moderating the thirft, without overloading the ar- 

 terial fyftem, and bringing on that tenfion and plenitude 

 liable to be produced by fwallowing too large a proportion 

 of liquids. 



In the ufe of water in acute difeafes, the temperature 

 Ihould be particularly attended to. As a general rule it 

 may be laid down, that the temperature of diluents at the 

 different periods of a cold, hot, and fweating ftage of a Am- 

 ple febrile paroxyfm, fhould be hot in the firft cafe, cold in 

 the fecond, and tepid in the third ; and it is chiefly in the 

 facond ftage that the quantity may be moft liberal. 



Moft of the above remarks are equally applicable to 

 the ufe of water in chronic difeafes in general, but more 

 efpecially in the deranged funftions of the ftomach and 

 bowels and biUary organs, occafioned by a long and habitual 

 indulgence in high food, ftrong drink, and all the luxuries 

 of the table, and which are well known to be fo decidedly 

 benefited by the ufe of water as a medicine. As in acute 

 difeafes, fo in chronic affeftions likewife, it is often of great 

 importance to attend to the temperature of the water. A 

 draught of cold water, for example, will often induce fick- 

 nefs and other dillrefling fymptoms in delicate dyfpeptic ha- 

 bits, while water rendered /lightly tepid may be taken with 

 impunity and even advantage. On the other hand, the ha- 

 bitual ufe of warm water or drinks is to be avoided, and 

 doubtlefs always does much harm. 



We fliall clofe thefe remarks by a quotation from Dr. 

 Saunders on the habitual ufe of water. " Water-drinkers," 

 fays this eminent writer, " are in general longer livers, are 

 lefs fubjeft to decay of the faculties, have better teeth, more 

 regular appetites and lefs acrid evacuations, than thofe who 

 indulge in a more ftimulating diluent for their common 

 drink." 



For the external ufes of water, fee the articles Bath 

 and Bathing, where this part of the fubjeft is treated at 

 length. 



On the general Contents of Mineral Waters and their Opera- 

 tion. — The proportions of fahne and other ingredients in 

 mineral waters are for the moft part fo fmall, as apparently 

 to be infufficient for explaining the elfeAs they often pro- 

 duce upon the animal economy. Many attempts, therefore, 

 have been made to explain this circumftance by different 

 writers, and the fubjeft is fo interefting, that we cannot let 

 it pafs without making a few remarks upon it. 



Dr. Saunders, one of the lateft and beft writers on mine- 

 ral waters, very properly ridicules the idea of Jpeeijic and 

 other myfterious properties, by which the older authors at- 

 tempted to explain their operation. This intelligent phyfi- 

 cian fuppofes, that a very great proportion of their effefts 

 depends fcl-ly upon the diluent operation of the water itfelf. 

 Of this, as we formerly obferved, there can be no doubt, in 



many inilances ; and even in all, the mere bulk and tempera- 

 ture of the water muft be allowed to produce a certain pro- 

 portion of the effefts. Still, hov^ever, innumerable inftances 

 occur, in which thefe are infufficient to explain the whole, 

 even when aided by the additional circumftance of great 

 dilution, on which the above eminent phyfician likewife lays 

 great ftrefs. The matter, therefore, has always appeared 

 fiifficiently puzzUng, and it is only lately that a little light 

 has been thrown upon it by the ingenious views of Dr. 

 Murray, which will be more fully explained in the next 

 feftion. 



There can be no doubt that foluble falts in general are 

 capable of exerting a much more powerful effeft upon the 

 animal economy, ceeteris paribus, than thofe which are info- 

 luble. The muriates are the moft foluble clafs of falts oc- 

 curring in waters, and are moreover, independently of this, 

 the moft aftive ; at leaft, this is the cafe with the earthy 

 muriates, efpecially the muriate of lime. Now this fait. 

 Dr. M. has rendered it probable, exifts in all mineral waters 

 found by the ufual analytic method to contain the ful- 

 phate of lime and muriate of foda, which comprehend by 

 far the greater number. The fame ingenious author has 

 alfo rendered it probable, that iron 'not unfrequently exifts 

 in the ftate of muriate inftead of carbonate, as commonly 

 believed, as for example, in the Bath waters. With thefe 

 views in general we perfeftly coincide, and have no doubt 

 that, in many inftances, a large proportion of the good ef- 

 fefts of mineral waters arifes from the muriates they con- 

 tain ; but we muft confefs that many difficulties flill appear 

 to ua to remain on this obfcure fubjeft, which cannot, in the 

 prefent ftate of our knowledge, be fatisfaftorily explained. 



Anal^is of Mineral Waters. — The analyfis of mineral 

 waters has been juftly deemed one of the moft difficult pro- 

 blems in praftical chemiftry. This arifes partly from the 

 diverfified nature of the ingredients, and partly from the 

 minute proportions in which fome of them exift. The cele- 

 brated Bergman was the firft chemift who prefented the 

 world with a general method or formula for analyfing mine- 

 ral waters. This was efteemed excellent in its day, and 

 even at the prefent time may be confidered valuable. Twenty 

 years afterwards, Mr. Kirwan pubhfhed an eflay on the fub- 

 jeft, which not only comprifed all that had been previoufly 

 done, but contained many valuable additions made by 

 himfelf. He alfo propofed a new method of analyfis, of 

 which we fhall give a fhort account hereafter. 



a. The firft ftep in the examination of a mineral water, 

 is to notice accurately its fenfible properties, fuch as its tem- 

 perature, colour, tranfparency, tafte, fmell, &c. 



b. The fecond ftep is to alcertain its fpecific gravity, the 

 fpontaneous changes it undergoes on expofure to the air, 

 the application of heat, &c. 



c. Thefe prehminary operations being performed, the next 

 objeft of inquiry, is to endeavour to obtain a knowledge of 

 the different ingredients prefent by means of reagents, or tefls, 

 as they are ufually termed. We have already mentioned the 

 different ingredients commonly met with in mineral waters, 

 and fhall now proceed to give a hft of the different tejls by 

 which their prefence may be detefted. For this lift we are 

 chiefly indebted to Dr. Thomfon, who has compiled it from 

 Kirwan and others. 



1 . The Gafeous Subjlances may be feparated from water, by 

 boiling it in a retort connefted with a pneumatic appara- 

 tus, and their nature and proportions may be afcertained in 

 the manner to be prefently defcribed. 



2. Hydrogen and its Compounds. — Sulphuretted hydrogen is 

 readily diftiuguifhed by its peculiar fmell, by its reddening 

 litmus fugacioufly, and by its blackening paper dipped in fo- 



lution 



