CH. xxxvn.] MINERAL SALTS IN URINE. $6t 



Chlorides. The chief chloride is that of sodium. The inges- 

 tiou of sodium chloride is followed by its appearance in the urine, 

 some on the same day, some on the next day. Some is decom- 

 posed to form the hydrochloric acid of the gastric juice. The 

 salt, in passing through the body, fulfils the useful office of 

 stimulating metabolism and secretion. 



Sulphates. The sulphates in the urine are principally those 

 of potassium and sodium. They are derived from the metabolism 

 of proteids in the body. Only the smallest trace enters the body 

 with the food. Sulphates have an unpleasant bitter taste (for 

 instance, Epsom salts) : hence we do not take food that contains 

 them. The sulphates vary in amount from i '5 to 3 grammes daily. 



In addition to these sulphates there is a, small quantity, about 

 one-tenth of the total sulphates, that are combined with organic 

 radicles : these are known as ethereal sulphates, and they originate 

 from putrefactive processes occurring in the intestine. The chief 

 of these ethereal sulphates are phenyl sulphate of potassium and 

 indoxyl sulphate of potassium. The latter originates from the 

 indole formed in the intestine, and as it yields indigo when treated 

 with certain reagents it is sometimes called indican. It is very 

 important to remember that the indican of urine is not the same 

 thing as the indican of plants, which is a glucoside. Both yield 

 indigo, but there the resemblance ceases. 



The formation of these sulphates is somewhat important ; the 

 aromatic substances liberated by putrefactive processes in the 

 intestine are poisonous, but their conversion into ethereal 

 sulphates renders them harmless. 



The equation representing the formation of potassium phenyl-sulphate is 

 as follows : 



C 8 H 6 OH + S0 a < = s a < 6H|S + H a O 



[Phenol] (Potassium [Potassium [Water] 



hydrogen phenyl-tmlphate] 

 sulphate] 



Indole (C 8 H T N) on absorption is converted into indoxyl 



The equation representing the formation of potassium indoxyl-sulphate is 

 as follows : 



<'HH T NO + so a <{? = so a < H N + H,O 



[Indoxyl] [PotanHium (rotawiuin (Water). 



liv.liM.jvn indoxyl-nulphate] 

 sulphate) 



Carbonates. Carbonates and bicarbonates of sodium, calcium, 

 magnesium, and ammonium are only present in alkaline urine. 

 They arise from the carbonates of the food, or from vegetable 



K.P. o o 



