

CHAP. XXXIV.] SULPHATES AND PHOSPHATES. 503 



water ; the latter having been previously held in solution in the urine by some 

 material which has been destroyed by a red heat. Although the presence of 

 certain acids and certain bases in the ash is readily demonstrated, the precise 

 manner in which these were originally united together is not so easily 

 ascertained. 



The most important saline constituents of normal urine are chlorides, 

 sulphates, and phosphates ; and the following bases are present, potash, soda, 

 lime, magnesia, with traces of silica and peroxide of iron. 



Chlorides. The chlorine exists in combination with sodium, in the form of 

 common salt, and perhaps also occasionally as hydrochlorate of ammonia. 

 Almost the whole of the chloride of sodium is probably derived from the 

 food ; although from recent investigations, it appears probable that this sub- 

 stance plays an important part in the development of tissues, and also in 

 certain morbid changes. In growing tissues, it is always abundant, and in the 

 fluid on the surface of healing ulcers it exists in large quantity.* 



Sulphates. The sulphuric acid exists in combination with potash, and 

 perhaps also with soda. The sulphates are highly important saline consti- 

 tuents, and their proportion is much influenced by the activity of the vital 

 functions, and also by an animal diet. After exercise, the amount of the 

 sulphates, as well as that of the urea, undergoes an increase ; and it has been 

 found, that in Chorea (a disease characterized by inordinate action of the 

 muscular system) a large quantity of these salts are excreted in the urine.f 

 The sulphuric acid is, doubtless, in great measure produced by the oxidation 

 of the sulphur contained in the proteine compounds. Unlike the chlorides, 

 the sulphates are not present, or are only met with in very small quantities, 

 in the fluids of the body generally, with the exception of the urine, a circum- 

 stance which points to the importance of the former in the organism, while it 

 clearly shows that the latter are not required in the nutritive changes, and are, 

 therefore, only to be found in the excrements. 



Sulphuretted Hydrogen is from time to time detected in urine. Dr. Beale 

 met with it frequently in the urine of insane patients. Sulphur is no doubt 

 eliminated in considerable quantity in the urine in certain cases. Cystine 

 contains as much as 26 per cent, of this substance. 



Phosphates. Phosphoric acid is found in combination with soda, lime, and 

 magnesia ; the salts thus constituted have been spoken of as alkaline or 

 earthy phosphates, the former term being confined to the combination of 

 phosphoric acid with soda, and the latter to the phosphates of lime and mag- 

 nesia, which are precipitated from healthy urine by the simple addition of 

 excess of ammonia. 



The large amount of phosphates present in urine is chiefly derived from 

 the food, but part results from the oxidation of the phosphorus which is con- 

 tained in the tissues ; the particular tissue concerned in the formation of 

 this phosphoric acid being the nervous, which, it is well known, contains a 

 large proportion of phosphorus. Dr. Bence Jones found an increase in the 

 quantity of the alkaline phosphates in the urine of some cases of inflamma- 

 tion of the brain, and a diminution in quantity in cases of delirium tremens 

 when no food was taken ; but in the latter case the diminution is, probably, 



* " On the Diminution of the Chlorides in the Urine in cases of Pneu- 

 monia," by Lionel Beale. Med. Chir. Trans., vol. xxx. 

 f Dr. Bence Jones. Med. Chir. Trans. 



