1276 



URINE. 



likewise have caused the precipitation of uric 

 acid, because the affinity of the former for 

 soda would then exceed that of the latter. 

 This explains the circumstance that urine, in 

 certain states, when from some cause or other 

 its amount of sulphuric, hippuric, or other 

 acid, becomes increased, precipitates a larger 

 proportion of uric acid than urine in its 

 normal state. The solubility of uric acid in 

 urine must decrease in proportion as the 

 amount of the other acids present in the 

 urine increases, because those acids share the 

 soda with the uric acid ; and, of course, the 

 larger the amount of soda which combines 

 with these other acids, the less comes to the 

 share of the uric acid. It is likewise owing 

 to this, that uric acid very frequently preci- 

 pitates from urine upon the addition of mineral 

 or other acids, and that urine of a turbid, 

 whey-like appearance, from the presence of 

 uric acid, frequently manifests a far more 

 strongly acid reaction than normal urine. 



" Now, bearing in mind that the use of 

 alkaline citrate (Gilbert Blane), of neutral 

 paratartrate of potass, bi-tartrate of potass, 

 tartarised soda, acetates of potass and soda, 

 and tartarised borax, renders the urine alkaline 

 by creating in it an amount of carbonated 

 alkali ; and that, likewise, after the eating of 

 fruit, such as cherries, strawberries, c., the 

 urine is of an alkaline nature, inasmuch as 

 these fruits contain alkalies combined with 

 vegetable acids, it is obvious that the acid re- 

 action of healthy urine is purely accidental, 

 and that urine of an alkaline or neutral re- 

 action cannot be considered as a symptom of 

 a diseased condition of the body. All vege- 

 table aliments, without exception, tubers, 

 roots and leaves, potatoes, turnips, greens, 

 &c., contain alkalies in combination with ve- 

 getable acids ; potatoes, for instance, contain 

 alkaline citrates ; turnips, alkaline racemates 

 and oxalates, &c. All these plants yield, 

 upon incineration, more or less strongly alka- 

 line ashes, the bases of which were contained 

 in the living plants, as salts of vegetable acids. 



" It is obvious that by adding these vege- 

 tables to a meat diet, to bread and to other 

 aliments prepared from flour, the nature of 

 the urine must become thoroughly altered ; 

 for the alkalies which these vegetables con- 

 tain in combination with vegetable acids, enter 

 the urine in the form of carbonated alkalies, 

 and neutralise the acids, of whatever kind, 

 which may be present. When partaken of in 

 a certain proportion, they render the urine 

 neutral ; when partaken of in a larger pro- 

 portion, they impart to it an alkaline reaction. 



" The urine of all animals feeding upon 

 vegetables, such as grass, herbs, roots, &c., 

 has an alkaline reaction. The urine of the 

 horse, of the cow, of the sheep, of the camel, 

 of the rabbit, of the guinea-pig, of the ass, &c. 

 is alkaline ; it contains alkaline carbonates, 

 and acids produce in it a lively effervescence. 

 " The acid, neutral, or alkaline reaction of the 

 urine of healthy individuals does not depend 

 upon any difference in the processes of di- 

 gestion, respiration, or secretion, in the various 



classes of animals, but upon the constitution 

 of the aliments, and upon the alkaline bases 

 which enter the organism through the medium 

 of these aliments. If the amount of these 

 bases is sufficiently large to neutralise the 

 acids formed in the organism, or supplied by 

 the aliments, the urine is neutral , whilst it 

 manifests an alkaline reaction when the 

 amount of alkaline bases thus supplied to the 

 organism is more than sufficient to neutralise 

 the acids; but in all these cases the urine 

 accords with the nature of the aliments taken. 



" The inorganic bases and acids contained 

 in the urine were, with the exception of sul- 

 phuric acid, which joins them in the organism, 

 constituents of the aliments. The amount 

 of inorganic bases and acids emitted through 

 the urine in twenty-four hours must, in adult 

 individuals, be equal to that of these bases 

 and acids supplied to the organism, during 

 the same period, through the medium of the 

 aliments. 



"From these data it follows necessarily, 

 first, that the analysis of urine when made 

 without respect to the inorganic salts, acids, 

 and bases, supplied by the aliments, teaches 

 nothing whatever, and by no means justifies 

 us in drawing therefrom any physiological or 

 pathological inference ; secondly, that from 

 the nature of the ashes of the aliments we 

 are able to determine, positively, the con- 

 stituents of the urine emitted ; and thirdly, 

 that only when these latter have been dis- 

 tinctly ascertained, can we expect to derive, 

 from the analysis of the urine, any correct 

 information with respect to the inorganic 

 matters which have come to be present in it 

 through processes of disease ; this, at least, is 

 the chemical method of quantitative investiga- 

 tion. 



" Bearing in mind that the urine contains 

 the soluble constituents of the ashes of the 

 aliments, whilst the faeces contain the insolu- 

 ble part of these constituents, we may form 

 an accurate knowledge of both, at once de- 

 termine in which urine soluble alkaline phos- 

 phates must be present, and in which they 

 cannot exist. The ashes of all seeds, and of 

 flesh and blood, contain a certain amount of 

 soluble and insoluble phosphates, whilst the 

 ashes of vegetables contain no free alkaline 

 phosphate, but only insoluble phosphates. 

 These vegetable ashes contain far more lime 

 and magnesia than is required for the neutral- 

 isation of the phosphoric acid present. 

 Hence, upon incinerating a plant, together 

 with its seed, and lixiviating the ashes, we find 

 no alkaline phosphate in the fluid obtained, 

 although the lixivium of the ashes of the 

 seeds, when incinerated and lixiviated by 

 themselves, yields a considerable amount of 

 these phosphates : the excess of lime and 

 magnesia contained in the leaves and the 

 straw enter here into combination with the 

 phosphoric acid of the soluble alkaline phos- 

 phates, forming an insoluble compound. 



" It will now be understood why the alka- 

 line phosphates are generally absent from the 

 urine of herbivorous animals, and also why, 



