248 THE UEIXE. 



substances occur preformed also in many articles of food. We con- 

 sequently recognize two sources of the aromatic bodies which are 

 found in the urine, viz., the aromatic bodies which enter into the 

 composition of our diet as such, and those which result from the 

 destruction of albumins through the activity of micro-organisms. 

 Under certain pathological conditions, further, substances of this 

 character may also be formed in the body proper, owing to degenera- 

 tive changes, which may or may not be the result of bacterial action. 

 Under normal conditions, however, this source scarcely enters into 

 consideration. 



The Conjugate Sulphates. 



Paracresol, phenol, hydroquinon, pyrocatechin, indpl, and skatol 

 are largely eliminated in the urine in combination with sulphuric 

 acid as sodium or potassium salts. But while paracresol and its 

 derivatives combine with sulphuric acid directly, indol and skatol 

 are previously oxidized to indoxyl and skatoxyl, as has been shown. 

 Conjointly the resulting compounds are spoken of as the conjugate 

 or ethereal sulphates of the urine. Their daily excretion in man 

 corresponds to about one-tenth of the mineral sulphates, viz., from 

 0.094 to 0.620 gramme, under normal conditions. Increased 

 amounts are observed when from whatever cause the intestinal 

 putrefaction is increased. It is to be noted, however, that the ratio 

 between the individual substances is even normally not constant, 

 and it seems that the relative preponderance of the one over the 

 other is primarily referable to the extent to which individual groups 

 of micro-organisms are active. In some instances we may thus find 

 that the increase in the conjugate sulphates is referable to an increased 

 production of indol and skatol, while in others phenols are largely 

 formed. 



Aside from an increase in the degree of intestinal putrefaction, 

 larger amounts of the conjugate sulphates may also be observed if 

 putrefactive processes are taking place within the body proper, pro- 

 viding that active resorption occurs from the diseased area. An 

 increased elimination is also noted when any of the aromatic sub- 

 stances mentioned are ingested as such or otherwise introduced into 

 the circulation from without. A notable increase is thus observed 

 in poisoning with carbolic acid or its congeners, and is then, of 

 course, principally owing to an increased formation of phenol sul- 

 phates. The ingestion of ortho-nitro-phenyl-propiolic acid, which 

 is reduced to indoxyl within the body, similarly leads to an increased 

 elimination of indoxyl sulphate. 



The synthesis of the various conjugate sulphates is probably 

 effected within the liver, but may also occur in other organs of the 

 body. Their quantitative estimation in toto has been described. 



The Phenols. Of the phenols which occur in the urine, para- 

 cresol is the most abundant ; next in order comes phenol, while 

 pyrocatechin and hydroquinon are found only in traces. Besides 



