THE URINE. 391 



with the glycocoll of hippuric acid, it seems also that the aromatic 

 nucleus itself may be protected from destruction in the organism 

 by syntheses with other bodies. The aromatic ethereal sulphuric 

 acids are examples of this kind. 



The difficulty in deciding whether the benzol ring itself is 

 destroyed in the body lies in the fact that we do not know all the 

 different aromatic transformation products which may be pro- 

 duced by the introduction of any aromatic substance in the 

 organism and which we must seek for in the urine. On this 

 account it is also impossible to learn by exact quantitative estima- 

 tions whether or not an aromatic substance introduced or absorbed 

 appears again in its entirety in the urine. Certain observations 

 render it probable that the benzol ring, as above mentioned, is at 

 least in certain cases destroyed in the body. SCHOTTEN and BAU- 

 MANN" have found that certain amido-acids, such as tyrosin, 

 plienylamido-proinonic acid and amido-cinnamic acid, when intro- 

 duced into the body cause no increase in the quantity of known 

 aromatic substances in the urine; this makes a destruction of these 

 amido-acids in the animal body seem probable. JUVALTA also 

 made an experiment on dogs with phthalic acid and found 

 that 57.5-68.76$ of the acid introduced into the body disappeared, 

 or more correctly was not found again. According to JUVALTA, 

 this acid does not undergo any synthesis, nor does it yield any 

 aromatic transformation products ; and if this supposition be correct, 

 we have here a proof of the destruction of the benzol nucleus of a 

 part of the phthalic acid introduced into the organism of the dor, 



An oxidation in the side chain of aromatic compounds is often 

 found and may also occur in the nucleus itself. As an example, 

 benzol is first oxidized to oxybenzol (ScHULTZEN" and NAUNYN), 

 and this is then in part converted into dyoxybenzols (BAUMAiO" and 

 PREUSSE). Naphthalin appears to be converted into oxynaphthalin 

 and probably a part also into dioxynaphthalin (LESLIE: and M. 

 NENCKI). Anilin, C 6 H 5 .NH 2 , passes into paramidophenol, which 

 passes into the urine as ethereal sulphuric acid, H 2 N.C 6 H 4 .O.S0 2 .OH 

 (F. MTJLLEE). 



If the aromatic substance has a side chain belonging to the fatty 

 series, this last is generally oxidized. For example, toluol, C 6 H 6 .CH 3 

 (SCHULTZEN and NAUNYN), ethyl-benzol, C 6 H 5 .C 2 H 6 , and propyl- 



