^BERKELEY] PENTOSE COMPOUNDS 43 



in the case of inosinic acid, these authors have shown that considerably 

 less than the theoretical amount of furfurol is obtained by distillation 

 with hydrochloric acid of specific gravity 1.06.^ In the absence of 

 knowledge of the furfurol equivalents of the pentoses present it 

 seemed best to calculate on the basis of a known relationship. The 

 results thereby obtained are comparable amongst themselves and 

 with those obtained by Grund. 



The possibility of errors being introduced into the method of 

 determination by substances other than pentoses which might be 

 present in animal tissues is discussed in some detail by Grund. The 

 conclusion is reached that glycogen is the only compound likely to 

 remain after exhaustive treatment with alcohol and ether which could 

 introduce an appreciable error, and this only in the case of the liver. 

 Of the tissues dealt with in this paper only the livers (digestive glands) 

 of the mollusks contained enough glycogen to effect the pentose 

 determinations. Samples of all the livers and many of the other 

 tissues were treated by Pfîuger's method of glycogen determination. 

 The glycogen found was distilled with hydrochloric acid and the 

 distillate treated with phloroglucin according to the Tollens and 

 Krobe method of pentose determination, but only in case of the 

 molluskan livers was a weighable amount of precipitate obtained. In 

 these cases a corresponding correction has been applied to the pentose 

 determination. Small quantities of glycogen were found in a few 

 other tissues which are noted in the tables which follow. 



^Levene, P. A., and Jacobs, W. A., Ber. Chem. Ges., 1908, XLI, 2703, and 1909, 

 XLII, 1198. 



