AMINOACIDS IN NORMAL URINE 115 



with careful practice of precautions, capable of recovering 

 95 to 98 per cent. 



ELIMINATION OF THE AMINOACIDS 



The above consideration of the part of glycocoll in inter- 

 mediate metabolism serves to introduce another interesting 

 problem, that of the conditions under which the a-amino acids, 

 the essential products of the catabolism of the protein mole- 

 cule, may escape the normal combustion and appear in 

 appreciable quantity in the urine. 



Aminoacids in Normal Urine. That a-aminoacids, at 

 least their optically active forms, which are normally struc- 

 tural parts of the proteins, may easily undergo complete 

 disintegration is beyond question and has been proven 

 experimentally many times; although in case of artificial 

 introduction of formed aminoacids it has been proved that 

 a portion sometimes escapes as such in the urine. 50 Nor- 

 mally, the amount of aminoacids in the urine is, of course, 

 quite small. Different explanations have been proposed for 

 this fact, as it has been determined that hippuric acid in 

 standing urine is very readily subject to cleavage 51 from 

 action of bacteria, and its glycocoll may then be detected 

 by the naphthalinsulphochloride method. Other aminoacids 

 than glycocoll have apparently thus far not been certainly 

 obtained from normal urine. 52 However, it might be easily 

 conceived how, if small quantities of glycocoll, which had 

 escaped synthesis into hippuric acid or had been produced 



50 E. Abderhalden and P. Bergell, Zeitschr. f. physiol. Chem., 39, 10, 1903; 

 K. Stolte (F. Hofmeister's Lab., Strassburg), Hofmeister's Beitr., 5, 15, 1904; 

 M. Plaut and H. Reese (under direction of G. Embden), Hofmeister's Beitr., 

 7, 425, 1905; E. Reisz, ibid., 8, 332, 1906; S. Oppenheimer, ibid., 10, 273, 1907; 

 R. Hirsch, Zeitschr. f. exper. Pathol., 1, 141, 1905; E. Abderhalden and J. 

 Markwalder, Zeitschr. f. physiol. Chem., 72, 63, 1911; E. Abderhalden, A. 

 Furmo, E. Goebel and P. Stttbel, ibid., 74, 481, 1911. 



n Y. Seo (Minkowski's Clinic, Greifswald), Arch. f. exper. Pathol., 58, 440, 

 1908. 



M E. Abderhalden and A. Schittenhelm, Zeitschr. f. physiol. Chem., 47, 

 339, 1906. 



