vii KATABOLIC CONSTITUENTS OF UEINE 403 



carcinoma, in various anaemic and leucaemic conditions. According 

 to Boeri and Keale, acetonuria is generally induced by the condi- 

 tion which causes oxaluria, and an excessive formation of acids in 

 the body, viz. diminished gas-exchanges, and depression of the 

 oxidising processes in the tissues. In fact, on obstructing 

 pulmonary ventilation in dogs by applying Sayre's jacket to the 

 thorax, they obtained marked modifications in the katabolic tissue- 

 processes, characterised by increased consumption of proteins, 

 excessive formation of acids, oxaluria, and acetonuria, with 

 corresponding increase of ammonia in the urine. 



Urine also contains a derivative of glucose, which has the 

 characteristics of the aldehydes and acids, and can be readily 

 interchanged with sugar on account of its marked reducing power. 

 This is glycuronic acid (C 6 H 10 4 ). In normal urine there is, 

 according to Schmiedeberg, a small quantity of glycuronic acid 

 combined with phenol, indoxyl, and scatoxyl with which it forms 

 glycuronic esters, which readily split up when treated with 

 mineral acids. 



On the exhibition of certain poisons or drugs, the quantity of 

 glycuronic acid in the urine increases considerably. This is seen 

 in chloroform narcosis ; after the use of chloral, camphor, morphine, 

 curare, etc. The apparent glycosuria induced by these substances 

 is due to the glycuronic esters, and should therefore be termed 

 glycuronuria. 



Addition of beer yeast to the urine does not cause any marked 

 alcoholic fermentation, such as invariably appears in glycosuria. 

 The glycuronuria due to drugs is transitory and has only a 

 clinical interest. The rare cases of spontaneous glycuronuria, on 

 the contrary, i.e. such as are not produced by poisons or drugs, 

 are interesting not because they represent any dangerous alteration 

 in the katabolic tissue processes like diabetes, but because they 

 elucidate the physiological problem of the origin of glycuronic 

 acid. For the present we must confine ourselves to the chemical 

 researches by which glycuronic acid has been obtained from sugar ; 

 and from which we learn that this acid is an intermediate product 

 of carbohydrate metabolism. It probably appears in the urine 

 when it escapes complete oxidation, by combining with the 

 aromatic bodies or with other substances foreign to the ordinary 

 diet or the normal katabolism of the tissues. In the same way 

 glycocoll escapes oxidation by combining with the benzoic acid, 

 and appears in the urine in the form of hippuric acid. 



Pentoses also can be isolated in the urine, particularly after 

 the ingestion of fruits that contain them (alimentary pentosuria). 

 A spontaneous pentosuria has also been noted, without any 

 apparent external cause (Salkowski and Jastrowitz, 1892). 

 Luzzatto, who with Eeale has specially occupied himself with 

 pentosuria in Italy, was the first to isolate an active pentose 



