DISEASES OF THE KIDNEYS, 745 



paper ; it is also soluble in etlier and alcohol. Its quantity in 

 the urine varies greatly. When the quantity of urea is small 

 that of hippuric acid is almost always large, and vice versa. 

 According to Von Bibra and Boussingault it varies from 5 to 1 5 

 parts in 1000 of the urine of healthy horses ; and it has been 

 stated by some chemists that the urine of horses which are sub- 

 jected to very hard work contains no hippuric acid, but much 

 benzoic acid instead, " The last part of the statement," says 

 Mr, Gamgee, " seems doubtful, though it would appear that hard 

 work checks the excretion of hippuric acid, and increases the 

 quantity of urea excreted," The observations of Maack oppose 

 this conclusion. He found that horses kept standing in the 

 stable passed very little hippuric acid, but large quantities of 

 urea, and Dr. G-, Harley made similar observations regarding 

 London stall-fed cows. They did iiot, however, examine the 

 urine after these animals had been exercised ; their experiments 

 are therefore incomplete. Hippuric acid is increased in rheu- 

 matism, red water, and in diseases of the respiratory organs ; in 

 fact, in all conditions in which the blood is imperfectly aerated, 

 either from obstruction to free respiration or sudden arrestment 

 of the cutaneous functions, as well as from an imperfect condi- 

 tion of the blood itself, rendering it incapable of oxidation. 



Extractive matters, as creatine, creatinine, lactic acid, and 

 benzoic acid, which is transformed into hippuric acid in the 

 body — for it has been found that when benzoic acid is given to 

 an animal an almost equal amount of hippuric acid is elimi- 

 nated by the kidneys — are found in the urine. Sometimes urine 

 contains a large quantity of mucus derived from the pelves of 

 the kidneys, ureters, bladder, or urethra, indicating some degree 

 of irritation of the mucous membranes. After parturition, as 

 might be expected, the urine generally contains much mucus, 

 derived from the mucous membrane of the vagina. 



Saline matters, consisting of various materials from the food 

 and tissue, as the chlorides, phosphates, sulphates, and carbonates, 

 are present in healthy - urine, whilst other salts, originating in 

 mal-nutrition of tissues, or from defective secretion of other 

 organs, such as the oxalates, are sometimes met with. For the 

 method of determining the presence of these, the reader is referred 

 to Harley on the Urine, Eoberts on Urinary and Renal Diseases, 

 Beale, and others. The most common inorganic deposit which 



