URINE. 



1269 



hope of obtaining some fixed law whereon to 

 base a knowledge of the peculiar influence of 

 the several circumstances on which the varia- 

 tions depend. 



The chemical analysis of this complex fluid 

 was undertaken by Berzelius, who, with his 

 accustomed accuracy, produced a result in 

 which the various improvements and advances 

 in chemistry have rendered it necessary to 

 make but little change. 



The number of constituents of healthy 

 urine has been but little increased by discovery 

 since Berzelius wrote, one or two only having 

 to be added to his list. 



It will be our object to enumerate these 

 constituents, and describe such as may require 

 especial notice, before proceeding to consider 

 the quantitative analysis of the urine. 



The following, then, may be regarded as a 

 list of the constituents of healthy urine : 



Water. 

 Urea. 



Of 



i t- 



Extractive matters. 



fering 



Colouring matter. 



four kinds, dif- 

 in their reactions 

 and solubility in men- 

 strua. 



Of two kinds, brown, 

 (or Juvmaphfcbi), and 

 red (or wroerythrin}. 



Mucus. 

 Uric acid. 

 Hippuric acid. 

 Carbonic acid. 

 Lactic acid. 

 Sulphuric acid. 

 Hydrochloric acid. 

 Phosphoric acid. 

 Silicic acid. 

 Hydrofluoric acid. 

 Soda. 

 Potash. 

 Lime. 

 Magnesia. 

 Ammonia. 

 Oxide of iron. 



Other acids, peculiar to urine, have been 

 described by authors, but their qualities are 

 not sufficiently determined to admit of their 

 being yet classified as constituents. 



Urea. This constituent of the urine has 

 been supposed by some to form during the 

 evaporations necessary for its extraction. 

 This, however, is not the case, as I have been 

 able to obtain it by agitating the officinal 

 rectified ether with urine in the natural 

 state, and then allowing the ethereal solution, 

 which separates above the urine, to evaporate 

 spontaneously. The urea so obtained is free 

 from lactic acid, showing that the view of 

 MM. Cass and Henry, who consider urea to 

 exist in urine in the form of lactate, is in all 

 probability erroneous. 



Urea possesses the following ultimate con- 

 stitution : 



C2, N2, H4, O2. 



Its chemical properties are as follows : 



When heated on platinum foil it fuses, and 

 on the heat being urged, it yields fumes of 



carbonate of ammonia. It is very soluble in 

 both cold and warm water. 



A concentrated solution of urea will bear a 

 heat of 212 Fahr. without decomposition, 

 but it quickly decomposes at that temperature 

 when in dilute solution. 



Alcohol of specific gravity 0*816 dissolves 

 one-fifth of its weight of urea at 60 Fahr. ; 

 boiling alcohol dissolves nearly its own 

 weight. 



LTrea is slightly soluble in ether. 



The caustic alkalies boiled with urea de- 

 compose it into carbonate of ammonia. 



The nitric and oxalic acids combine with 

 urea, forming more or less insoluble salts, and 

 on this fact the processes for the extraction 

 of urea, from its combinations, chiefly de- 

 pend. 



Urea possesses neither an acid nor alkaline 

 reaction. Its crystalline form is that of a 

 four-sided prism. 



Extractive matters of Urine. There are 

 four of these extractives ; one soluble in 

 alcohol as well as in water, and three soluble 

 in water, and not in alcohol. 



That which is soluble in alcohol may be ob- 

 tained from the urine by digesting alcohol of 

 specific gravity 0'833 on an extract of urine, 

 and after crystallising the urea by means of 

 nitric acid from the products of the alcoholic 

 solution dissolved in water, separating the un- 

 crystallisable matter, and neutralising it with, 

 carbonate of baryta ; the mass must then be 

 dried, and alcohol must be used to separate 

 the extractive from the barytic salt. 



Its chemical properties are as follow : 



When heated, it swells much, and leaves a 

 copious alkaline carbonaceous mass.* It red- 

 dens litmus paper. 



Neither bi-chloride of mercury, nor the 

 acetate of lead, is capable of precipitating its 

 watery solution.f 



Both acid and alkaline solutions are inca- 

 pable of effecting any precipitation of this ex- 

 tract, from its solution in water. 



Protochloride of tin, nitrate of silver, and 

 di-acetate of lead, produce precipitates. 



It may be well to mention, that if anhy- 

 drous alcohol be digested on this extractive, 

 which has been called osmazome, it is capable 

 of being divided into two portions ; the one 

 soluble and the other insoluble in that fluid. 



The property of being precipitated by the 

 di-acetate of lead, nitrate of silver, and pro- 

 tochloride of tin, belongs peculiarly to that 

 part of the extractive matter which is soluble 

 in anhydrous alcohol. 



Animal txtractive soluble in water only. 

 This may be procured by dissolving in water 

 an extract of urine, which has been digested 

 with alcohol of specific gravity 0'833. By 

 the re-solution we separate any vesical mucus, 

 lithic acid, earthy phosphate, or silica, which 

 may be contained in the mass. The solution 



* It contains an alkaline lactate. 



f If these salts produce a precipitate, it is because 

 alcohol has been used of higher specific gravity 

 than U 833. 



4 M 3 



