1904] 



Studies on Enzyme Action. 



529 



completed, the values in the last column are no longer constant but 

 increase; after 134 hours, the value of a D actually rises above that 

 corresponding to complete conversion into glucose and galactose. This 

 increase was presumably to be ascribed to the formation of compounds 

 of high specific rotatory power from the products of change : to test the 

 correctness of this conclusion, experiments were made in which 

 solutions of glucose and galactose were heated at 60° during several 

 hours with chlorhydric acid of the strength used in the previous 

 experiments. As Tables II and III show, in each case, a rise in a D 

 was observed but the rotatory power did not become constant until 

 after about 250 hours, equilibrium being only slowly established 

 between the monosaccharide and its reversion products. The departure 

 during the later part of hydrolysis from the logarithmic law may 

 therefore with some degree of probability be ascribed to some form of 

 reversible change. It may be pointed out that Wohl* has observed 

 a similar change in highly concentrated solutions of glucose and 

 fructose when these are heated with small quantities of chlorhydric 

 acid on the water bath; and that Fischerf prepared the biose 

 isomaltose by the action of cold strong chlorhydric acid on glucose. 



Table II. Table III. 



27 per cent. Glucose. 27 per cent. Galactose. 







Successive 







Successive 



Time in 





increase 



Time in 





increase 



hours. 



aD. 



per hour. 



hours. 



ccp. 



per hour. 







28°-67 









42°-75 





8 



28-85 



0-022 



8 



42-70 





16 



29-03 



0-022 



16 



43-03 



0-041 



22 



29-13 



0-016 



22 



43-23 



0-033 



44 



29-40 



0-012 



44 



43-50 



0-012 



96 



29-93 



o-oio 



72 



43-90 



0-014 



166 



30-42 



0-007 



96 



44-07 



0-007 



200 



30-58 



0-005 



166 



44-28 



0-003 



Hydrolysis of Maltose. — Owing to the great variation in the value of 

 K produced by alterations in concentration and temperature, it was 

 impossible to compare our results for milk sugar directly with those of 

 SigmondJ for maltose. Accordingly, the value of K was determined 

 for maltose under the conditions observed in our experiments with 

 milk sugar. 



* £ Ber.,' 1890, vol. 23, p. 2084. 

 t ' Ber,' 1890, vol. 23, p. 3687. 

 % Loc. cit. 



