56 CHEMICAL PHYSIOLOGY. 



as dibasic has the formula C 5 H 9 N0 5 , but which must 

 perhaps be considered as tetrabasic, and then has the 

 formula C 10 H 1S N 3 10 ; in that case its metallic salts will 

 have the general formula C 10 H 14 M 4 N 3 10 . Another 

 extractive acid is paraphanic acid, C n H 18 N~ 2 6 , dibasic. 

 Under some circumstances allantoine appears, C 4 H 6 N0 3 , 

 which can also be produced from uric acid artificially, 

 along with other remarkable products. Of inorganic 



Salts - salts the phosphates of lime and magnesia, and of 

 potash, and potassium chloride, are present in consider- 

 able quantity, but most prevalent is the sodium-chloride 

 or common salt. Of some matters minute traces appear 



Sol in the urine, thus of sugar and of alcohol, after these 

 bodies have been taken by deglutition. In diseases 



inS-edS 1 there may appear blood, albumen, fibrine (paraglobuline 

 and fibrino-plastic matter), fatty acids and fats, large 

 quantities of sugar, as in diabetes, leucine, tyrosine, 

 abnormal colourless matters yielding by acids uro- 

 cyanine and urorubine, as in cholera ; oxalic acid and 

 oxalate of lime, as in a particular disease which frequently 

 ends in the formation of calculi. Much as the urine 

 has been studied its chemistry is by no means accom- 

 plished, and on the causes of the most troublesome 

 diseases showing themselves by symptoms in the urine, 

 gout, uric acid calculus, oxalic diathesis, diabetes, chy- 

 lous urine, our knowledge is as yet very incomplete. 



Under all circumstances, however, the analysis of 

 the urine is an indispensable aid to clinical diagnosis, 

 and furnishes most valuable positive and negative 

 information on acute as well as chronic diseases. 



seat. The secretion of the skin, discharged in large quan- 



