134 MATERIA MEDIC A AND THERAPEUTICS. 



urine is most readily induced when the skin is kept cool, and 

 carries with it an excess of urea, phosphoric acid, and chloride 

 of sodium. Water is thus a diuretic, and in one sense the most 

 natural measure of the kind*, being indicated when we desire 

 simply to irrigate or flush the urinif erous tubules and urinary 

 passages, and wash from them the products of disease, such as 

 blood, leucocytes, cellular debris, and sediments. Some kinds 

 of calculi may be dissolved by the steady consumption of dis- 

 tilled water, which carries away minute traces of the stone, 

 whilst it prevents fresh accretion on the surface. 



As a diaphoretic, water acts best when warm and combined 

 with external heat. It is the basis of most familiar domestic 

 measures for relieving feverishness by inducing perspiration, 

 such as warm drinks of all kinds, and spirituous compounds. 



GROUP VI. 



THE CARBOHYDRATES AND OTHER CARBON 

 COMPOUNDS. 



ALCOHOL. ALCOHOL. C 2 H 6 O. 



Besides the following preparations, which are 

 commonly associated with alcohol, all the Tincturse, 

 Spiritus, and Essentiae, several of the Liquores, 

 Linimenta, and Misturae, and a few other compounds 

 contain it in various proportions. 



1. Alcohol. Absolute Alcohol. C 2 H 6 0. Used only in 

 chemical testing. 



Source. Made by shaking rectified spirit with carbonate of 

 potash ; decanting, and distilling with slaked lime. 



Characters. Colourless, free from empyreumatic odour, 

 Sp. gr., 0795. 



Impurities. Resins, or oil; detected by turbidity on dilu- 

 tion. Water; giving blue colour with anhydrous sulphate of 

 copper. 



ft. Spiritus Roetificsitns. Rectified Spirit. Alco- 

 hol, C 2 H 6 0, with 16 per cent, of water. 



Source. Obtained by the distillation of fermented saccharine 

 fluids. 



