1274 



URINE. 



" But the case is quite different with water 

 possessing an amount of salts equal to that of 

 the blood; if even as little as l-100th part of 

 common salt be added to pump-water, and 

 from three to four glasses drank, no evacua- 

 tion of urine will take place, even two hours 

 after drinking. It is almost impossible to drink 

 more than three glasses of this saline water, 

 for it weighs heavily on the stomach, as if the 

 absorbent vessels had no power of taking it 

 up. This obviously arises from the fluid with- 

 in the channels of circulation, i. e. the blood, 

 and the fluid without these vessels, i.e. the sa- 

 line water, not exercising any physical action 

 upon one another, i. e. not intermixing by 

 endosmose or exosmose. 



" Water containing a larger amount o. 

 salts than the blood, such as common sea- 

 water, for instance, and even the weaker kinds 

 of saline mineral waters, exercise again a dif- 

 ferent action from that of pump-water mixed 

 with 1-1 00th of common salt ; not only no 

 emission of urine takes place after the imbibi- 

 tion of such saline water, but water exudes 

 from the circulating vessels into the intestinal 

 tube, and, together with the saline solution, is 

 carried off through the rectum ; purgation 

 takes place, attended with much thirst, if the 

 saline solution be in some measure concen- 

 trated. 



" Considering that a certain amount of salts 

 is absolutely necessary to constitute normal 

 blood, we may deduce from these observations 

 and experiments (which any one may easily 

 imitate and verify upon his own person) that 

 the physical condition of the tissues or of the 

 bloodvessels opposes an obstacle to any in- 

 crease or decrease of the amount of salts in 

 the blood ; and thus that the blood cannot 

 become richer or poorer in salts beyond a cer- 

 tain limit. 



" Fluids containing a larger amount of salts 

 than the blood remain unabsorbed, and leave 

 the organism through the rectum ; fluids con- 

 taining a smaller amount of salts than the 

 blood enter into the circulation, absorb, and 

 remove from the organism, through the uri- 

 nary channels, all the soluble salts and other 

 substances which do not belong to the con- 

 stitution of the blood ; so that, finally, only 

 those substances remain in the organism which 

 exist in chemical combination with the con- 

 stituents of the blood, and which, therefore, 

 are incapable of being excreted by the healthy 

 kidneys. 



" 1 have convinced myself, by careful and 

 minute examinations, that urine emitted after 

 drinking a copious amount of water invariably 

 contains a somewhat larger amount of salts 

 than the water which has been drank ; whilst 

 the amount of phosphates contained in the 

 last emitted portions of the urine is extremely 

 minute, and no longer detectable by the ordi- 

 nary tests. It is, therefore, obvious that all 

 the salts, without exception, contained in the 

 urine, are to be considered as accidental con- 

 stituents of the blood, which are excreted and 

 removed from the organism precisely because 

 they no longer form part of the normal consti- 



tution of the blood. The phosphates emitted 

 with the urine were, previously, constituent 

 substances which have been decomposed in 

 the vital processes, or they existed as consti- 

 tuents of the blood, but upon its transforma- 

 tion into living tissues they were not admitted 

 into their composition, they were not required 

 in the constitution of the latter. 



" Now, among the products of the vital 

 processes, which, together with the soluble 

 phosphates, are removed from the organism 

 through the urinary organs and channels, there 

 are two organic acids, namely, uric acid and 

 hippuric acid, both possessing the property of 

 combining with the soda or potass of the 

 alkaline phosphates, and acquiring in the com- 

 bination a higher degree of solubility than they 

 possess, per se, at the common temperature of 

 the body. It is obvious that, by the accession of 

 these two acids, and by their action upon the 

 phosphates of soda, an unite and hippurate of 

 soda must be formed on the one hand, and 

 an acid phosphate of soda on the other ; and 

 that, consequently, the urine must acquire an 

 acid reaction. 



" But the presence of these two acids in the 

 urine is not the only cause of its acid nature , 

 there exists another cause, which tends pow- 

 erfully to maintain and increase it. 



" According to the preceding remarks we 

 ought to find in the urine all the soluble salts 

 of the food, as well as a small amount of the 

 phosphate of lime, which is soluble to a cer- 

 tain extent in acid fluids, together with mag- 

 nesia. The amount of these latter substances 

 will be in proportion to their solubility in acid 

 phosphate of soda. The other insoluble salts 

 of the aliments we ought to find in the faeces. 

 In other words, assuming that the materials 

 composing the aliments become converted into 

 oxygen compounds, that is, are burnt in the 

 organism, we ought to find in the urine all the 

 soluble salts of their ashes, and in the faeces 

 all the insoluble salts. Now, upon comparing 

 the constitution of the ashes of the blood or 

 of the aliments, or, rather, the salts contained 

 therein, with those contained in the urine, we 

 find that there exists a striking difference be- 

 tween their respective amounts of sulphates, 



" According to the analyses of the ashes of 

 the grains of wheat and rye*, the urine of an 

 individual feeding exclusively upon bread 

 ought not to contain a single trace of a sul- 

 phate, whilst the urine of an animal fed upon 

 peas or beans ought to contain sulphates toge- 

 ther with phosphates, in the proportion of nine 

 of the former to sixty of the latter. Finally, 

 as flesh contains no soluble alkaline sulphate 

 (broth does not yield any precipitate of 

 sulphate of barytes when tested with salts of 

 barytes), the urine of carnivorous animals 

 ought to be equally free from soluble sul- 

 phates. We find, on the contrary, that the 

 urine of man, according to the most correct 

 analyses, contains a far larger proportion of 

 sulphates than the aliments partaken of; nay, 

 even that the amount of the sulphuric acid 



* Ann. dor Chemie, Bel. xlvi. S. 79. 



