URINE. 



1275 



received into the system must, in many cases, 

 be equal or superior to that of the phosphoric 

 acid contained in the aliments. According to 

 the analysis of human urine made by Berze- 

 lius and Lehmanu, the amount of the sul- 

 phates present in urine is nearly double that 

 of all the soluble phosphates together. Hie- 

 ronymi found the amount of sulphate of 

 potass contained in the urine of the tiger, the 

 lion, and the leopard, compared with that of 

 the phosphates, to be as 1 to 7i. It can be 

 distinctly and positively proved that these 

 salts have not been partaken of in such pro- 

 portions. But we now know the origin of the 

 greatest portion of the sulphuric acid con- 

 tained in the urine; this acid has entered the 

 organism with the food, not in the form of a 

 sulphate, but as sulphur. 



" Gluten*, vegetable casein, flesh, albumen, 

 fibrin, and the cartilages and bones, contain 

 sulphur in a form quite different from the 

 oxygen compounds of this substance. This 

 sulphur is separated as sulphuretted hydrogen 

 during the putrefaction of these substances ; 

 it combines with the alkalies, operating upon 

 these animal substances, and may be ob- 

 tained from such combinations in the form 

 of sulphuretted hydrogen by means of stronger 

 acids. 



" Now, we know from the experiments of 

 Wohler, that the soluble sulphurets become 

 oxidised in the organism; and that thus, for 

 instance, sulphuret of potassium becomes con- 

 verted into sulphate of potass ; and it is there- 

 fore unquestionable that the sulphur of the 

 constituents of the blood, derived from the 

 aliments, or, what comes to the same point, 

 the sulphur of the transformed tissues be- 

 comes finally converted into sulphuric acid 

 by the ox}'gen absorbed in the process of 

 respiration, and thus that in the urine it must 

 appear in the form of sulphates ; and from 

 this cause the original amount of these salts 

 contained in the aliments becomes increased. 

 The alkaline base which we find in the urine, 

 in combination with this sulphuric acid, is 

 supplied by the soluble alkaline phosphates ; 

 and the latter, in consequence of the loss of 

 part of this base, are converted into acid salts. 



" By these considerations and views re- 

 specting the cause of the acid reaction of 

 urine, 1 have been induced to prepare an arti- 

 ficial urine, which possesses the properties of 

 natural urine, even although sulphuric^ acid 

 be altogether excluded. 



" If 40 grains of dry phosphate of soda 

 (or 90 grains of the crystallised salt, P O_, 2 



-{ H a ,. + 24< Aq.) be dissolved in one pound 



of water, a fluid will be obtained having an 

 alkaline reaction ; if to this fluid we add 15 

 grains of uric acid, and 15 grains of hippuric 

 acid, and the mixture is heated, both acids 



* Dietrich (in the laboratory of Giessen) has 

 examined gluten with regard to its amount of sul- 

 phur ; he found wheat-gluten to contain from 0-033 

 per cent, to 0-035 per cent, of sulphur, exactly the 

 same proportion as is contained in albumen or 

 fibrin. 



will completely dissolve, imparting a strong 

 acid reaction to the fluid. The solution thus 

 prepared does not deposit a trace of uric acid 

 at a temperature from 37 to 38 (=98, 100 

 Fahrenheit = the heat of the blood); nay, it 

 is even only several hours after complete re- 

 friiieration that a sediment is formed, consist- 

 ing of uric acid containing soda : this sediment 

 is of an analogous form to that deposited by 

 natural urine after standing at rest for a long 

 time. Upon collecting this sediment, in one 

 of my experiments, after the lapse of twenty- 

 four hours, I found that it weighed 7; 1 , grains, 

 so that there remained still in solution 22\ 

 grains of the organic acids. Dilute mineral 

 acids produce immediately, in the fluids fil- 

 tered off from the sediment, a precipitate of 

 uric acid. 



" Proust, Prout, and all the other chemists 

 who examined the urine previous to, or about 

 the same period as, Berzelius, ascribed its 

 acid reaction to the uric acid or phosphoric 

 acid; hippuric acid was not known as a con- 

 stant attendant upon uric acid. 



" It follows, from all we have hitherto 

 stated, that the acid nature of the urine of 

 carnivorous animals, as well as that of man, 

 depends upon the nature of the bases par- 

 taken of in the aliments, and upon the parti- 

 cular form of their combinations. In the 

 flesh, blood, and other parts of animals, as 

 well as in the grains of the cereal and legu- 

 minous plants, there exists no free alkali. The 

 alkali which these substances contain is in- 

 variably combined with phosphoric acid ; the 

 acids formed in the organism by the vital 

 process, namely, sulphuric acid, hippuric acid, 

 and uric acid, share the alkali amongst them ; 

 and this, of course, must give rise to the 

 liberation of a certain amount of phosphoric 

 acid, or, what comes to the same point, to the 

 formation of a certain amount of acid phos- 

 phates of soda, lime, and magnesia. The 

 proportional amount of the liberated phos- 

 phoric acid varies with the temperature ; at a 

 higher temperature the phosphate of soda 

 dissolves a larger amount of uric acid and 

 hippuric acid than at a lower temperature 

 at from 37 to 38 more than at 15. It is 

 owing to this that urine, upon refrigeration, 

 sometimes deposits uric acid, or urate of soda 

 in a crystalline state, which, of course, can 

 only take place by the uric acid, at a lower 

 temperature, restoring to the phosphoric acid 

 the soda or potass which, at a higher temper- 

 ature, it had withdrawn from it. At the 

 common temperature phosphoric acid decom- 

 poses urate of soda, whilst, at a higher tem- 

 perature, uric acid decomposes phosphate of 

 soda. When urine, containing uric acid, and 

 manifesting an acid reaction, forms no sedi- 

 ment upon cooling, it shows that the amount 

 of the phosphoric acid and that of the uric 

 acid exactly balance each other with regard to 

 their affinity for soda. Had there been pre- 

 sent a larger proportion of uric acid, this 

 would have separated upon cooling ; whilst, 

 on the other hand, the presence of a prepon- 

 derating proportion of phosphoric acid would 



