68 CA RBOH YDRA TESMONOSA CCHARIDES 



eliminated as such. It is not known whether or not glucuronic acid 

 is a normal intermediate product of glucose oxidation in the animal 

 body, or whether it is only formed under the exceptional condition of 

 the presence of certain toxic bodies. Large quantities of glucuronic 

 acid, in these ester-like combinations, appear in the urine when certain 

 drugs are introduced into the system. The following is a partial list 

 of the drugs which are eliminated in this manner : 



Isopropyl alcohol chloral 



Methyl propyl alcohol butyl chloral 



Methyl ethyl carbinol bromal 



Tertiary butyl alcohol dichloracetone 



Tertiary amyl alcohol a and /3 napthol 



Benzol turpentine 



Nitrobenzol camphor 



Aniline borneol 



Phenol menthol 



Resorcinol pinene 



Thymol antipyrine 



The elimination of these drugs in this manner constitutes a pitfall 

 for the unwary who may seek, after the administration of such drugs 

 as these to a patient, to investigate the urine for the presence of sugar 

 therein by the phenylhydrazine test, or its clinical modification known 

 as Cipollina's test. For glucuronic acid forms an osazone which may 

 easily be mistaken for glucosazone. The distinction may very readily 

 be made, however ; owing to the fact that the osazone of glucuronic 

 acid is decomposed by heating while that of glucose is not. If the 

 precaution be taken, therefore, of heating the precipitate on a boiling 

 water-bath for half an hour before examining it, no confusion of the 

 osazone of glucuronic acid with glucosazone is possible, for the osazone 

 of glucuronic acid is decomposed by this procedure and redissolves, 

 while the osazone of glucose remains unaltered. 



Glucuronic acid is therefore to be regarded as a protective agent 

 which guards the organism against the deleterious action of certain 

 substances introduced from without or, in some cases, from within the 

 body. Sometimes the glucuronic acid accomplishes its protective 

 function by combining directly with the toxic substance, rendering it 

 harmless until in the course of time it is eliminated; in other instances 

 the toxic substance unde^oes some degree of change and elaboration 

 before it is paired with glucuronic acid. Thus chloral hydrate and 

 butyl chloral undergo reduction before they couple with the glucuronic 

 acid; o-nitro toluol, on the contrary, is oxidized to nitrobenzyl-alcohol 

 before it pairs with glucuronic acid. Other substances undergo 

 hydration or both hydration and oxidation before they can couple with 

 the glucuronic acid. 



Glucuronic acid is possibly of importane not only as a carrier of 

 toxic substances out of the body, but also as a connecting-link between 

 the hexoses and the pentoses. It will be recollected that when a mono- 



