114 THE SECRETIONS: 



reaction is observed, and carbonate of ammonia is formed, 

 which causes more or less turbidity by precipitating the am- 

 moniaco-magnesian phosphate, and phosphate of lime. A 

 portion of these salts, associated with mucus, forms a greasy 

 whitish scum, in which, by means of the microscope, beautiful 

 crystals of ammoniaco-magnesian phosphate may be seen, mixed 

 with an amorphous mass of phosphate of lime and decomposed 

 mucus. On treating the urine in this state with hydrochloric 

 acid, it effervesces, in consequence of the presence of carbonate 

 of ammonia. If the urine is allowed to stand for a still longer 

 period, the smell becomes more disagreeable ; cubic, and four- 

 and six-sided prismatic crystals, composed of chloride of sodium, 

 hydrochlorate of ammonia, and phosphate of soda and ammonia, 

 are produced in consequence of the concentration produced by 

 the spontaneous evaporation, and the urine ultimately becomes 

 covered with a sort of mould, which is usually of a blue or 

 blueish-gray colour. 



"We have no certain knowledge regarding the manner in 

 which the acids and bases combine to form salts in fresh healthy 

 urine. We may fairly conclude that the chloride of sodium 

 preexists in it ; the sulphuric acid is generally supposed to be 

 united with potash, phosphoric acid with lime and magnesia, 

 and if (as is generally the case) more phosphoric acid be present 

 than is required for the saturation of these earths, the excess 

 combines with soda ; and if there be not sufficient soda present 

 to effect the saturation of the acid, the ammonia combines with 

 it, forming the biphosphate of ammonia. The lactic acid of the 

 urine is partly free, and partly combined with ammonia, potash, 

 and soda. Hydrochlorate of ammonia is also supposed to pre- 

 exist in the urine. Carbonic acid, when it occurs in the urine, 

 is held in solution and in a free state. Uric 1 acid is supposed 

 by Berzelius to exist in a free state in solution in the urine, 

 although warm urine usually holds a larger quantity of uric acid 

 in solution than an equal quantity of water at the same tempe- 

 rature could retain. There is, however, this point in favour 

 of his view, that the uric acid, which separates spontaneously 

 from the urine on cooling, contains mere traces of ammonia 



1 [It is stated in volume I, page 54, that the formula for hydrated uric acid is 

 C IO N 4 H 3 5 + HO. From various analyses of urates by Bensch (Liebig's Annalen, 

 vol. 54, p. 189), there is reason to believe that the true formula is C 5 N 2 H0 2 -}-HO.] 



