191 1] Isidor Greenwald 85 



Among the muscle extractives are a niimber of hasic substances 

 which contain the trimethyl groiip. Their small quantity indicates 

 that they are not primary cell constituents but decomposition 

 products derived from lecithans. 



Inosite is widely distributed in the animal organism, but muscle, 

 particularly cardiac muscle, is richer in it than is any other tissue. 

 Proof of the utilization of inosite in the animal body is still lacking. 

 When fed to rabbits none can be recovered from the urine. This 

 may be due to complete catabolism or to simple deposit in the 

 tissues. The latter supposition is strengthened by the occurrence 

 of inosite in the urine whenever the volume is much increased. 

 When injected subcutaneously, a large part of it is excreted in the 

 urine, probably owing to its appearance in the circulation in abnor- 

 mal concentration. That inosite is catabolized is indicated by the 

 results of Mayer^ who found considerable amounts of lactic acid 

 in the urine of rabbits to which he gave inosite subcutaneously. 

 He was, however, unable to obtain evidence of glycogen forma- 

 tion from inosite. These results are rather contradictory, for 

 Mandel and Lusk^ have shown that glucose can be formed from 

 lactic acid and it is difficult to understand why glycogen should not 

 have been formed from the inosite by way of lactic acid and glucose. 



Much importance was ascribed to nucleon, or phosphocarnic 

 acid, by Siegfried, but more recent investigations indicate that it is 

 not a chemical Compound but only a mixture of several products 

 obtainable from meat. 



The free hypoxanthin of muscle has been the subject of consid- 

 erable study but as yet we know little of its significance. The work 

 of Voegtlin and Jones^ has shown quite conclusively that muscle 

 tissue does not contain adenase and that consequently adenin is 

 probably not the precursor of the hypoxanthin of muscle. Burian* 

 showed that muscular work increased the excretion of uric acid and 

 purin bases in the urine ; also the amount of these substances in the 

 liquid used to perfuse isolated muscles. 



Two precursors of hypoxanthin suggest themselves, carnin and 



* Mayer: Biochemische Zeitschrift, 1907, ii, p. 393; 1908, ix, p. 533. 



* Mandel and Lusk: American Journal of Physiology, 1906, xvi, p. 129. 

 'Voegtlin and Jones: Zeitschrift für physiologische Chemie, 1910, Ixvi, p. 250. 



* Burian : Zeitschrift für physiologische Chemie, 1905, xliii, p. 532. 



