BIBLIOGRAPHY 431 



times with Ringer's fluid. He examined the perfusing fluid for 

 uric acid before and after perfusing it. 1 In some of the experi- 

 ments, the muscles were kept at rest, in others they were thrown 

 into tetanus by stimulating the spinal cord with an induced 

 current. 



It was found that before perfusion no purins could be detected 

 in the perfusing fluid, but that after perfusion purins appeared, 

 and that these were more abundant when the muscles had been 

 active. Of great interest was the further discovery that the 

 purin increase due to muscular activity existed not only during 

 the actual working time but for some time after it, and, further, 

 that the increase was largely in basic purins during the work, 

 and in uric acid in the following periods. These results entirely 

 agree with those obtained by an examination of the hourly purin 

 excretions. An examination of the muscles themselves also 

 showed an increase in the purin bases (hypoxanthin) as a result 

 of contraction. 



From these experiments Burian concludes that hypoxanthin 

 must be continually produced by the muscles, and that this pro- 

 duction is increased by muscular contraction. Before it gains 

 entrance into the blood, however, it is oxidised, by xanthin- 

 oxydase, into uric acid. Of the uric acid thus produced, a 

 portion is destroyed and a portion excreted, the proportion 

 varying in different species of animals (integral factor, p. 411). 

 This destruction is brought about by the destructive ferment. 



The following literature is referred to (by numbers) in the 

 text : 



1 Stadthagen, Virch. Archives, Bd. 109 (1887). 



2 Von Noorden, Lehrbuch der Pathologic des Stoffwechsels Berlin (1893). 

 S. 54 



3 Minfcowski, Arch. f. exper. Path. u. Pharmak., Bd. 41, S. 375. 



4 A. Kossel, Zeitschr. f. physiol. Chemie, Bd. 7, S. 19 (1882). 



5 Horbaczewski (vide Spitzer, No. 6). 



6 W. Spitzer, Arch. f. d. ges. Physiolog., Bd. 76, S. 192. 



7 Weintraud, Berlin klin. Wochenschr., Nr. 19 (1895). 



8 Hess and Schmoll, Arch. f. exper. Path. u. Pharmak., Bd. 37, S. 243 (1896). 



9 Burian and Schur, Arch. f. d. ges. Physiol., Bd. 80, S. 241. 

 10 Burian and Schur, the same, Bd. 87, S. 239 (1901). 



1 The fluid was perfused only once through the muscles, as it was found 

 that by repeated perfusion of the same fluid much of the uric acid disappeared. 



