( 103 ) 



were fouiul are then due to ti secondary reaction wliicli docs not 

 interfere with the study of the main reaction. 



The conchision should therefore rather l)c that the two ghicosidcs 

 arc directly converted into each other. 



5. The point in question would be solved with complete 

 certainty if tlie reciprocal transformation of a into /? were observed 

 in another solvent than methylalcohol. Excei)t in water these 

 ghicosidcs arc also slightly soluble in ethylalcohol. As aqueous 

 hydrochloric acid causes a resolution ijito sugar and methylalcohol 

 the behaviour of ethylalcoholic hydrochloric acid was investigated. 

 In this solvent the transformation also proceeded according to the 

 formula for reversible reactions, the same limit being reached as 

 when methylalcohol was used as solvent ^). 



6. The concentration of hydrochloric acid necessary to cause the 

 mutual transformation of the two isomers to take place with mea- 

 surable velocity, is tolerably large; much larger than is usually the 

 case in catalytic reactions. The possibility is therefore not exclu- 

 ded that HCl takes part in some unknown way in the i-eaction. This 

 theory is supported by the strongly retarding intluence of water on 

 the mutual transformation. 



For a HCl-concentration of L. 07 norm. ^4- /j' is about 0.0040. In the 

 presence of 1 mol. of H^O to 1 mol. of HCl. [about 2 \o\. 7o water] 

 in the solution k^k' was found to be reduced to 0.0012. If to 1 HCl, 

 5 Hj was added [about 10 vol. 7o of water], the transformation 

 took place exceedingly slowly, k -\~ k' = 0.0001 ; in this case a little 

 glucose was also formed. 



Finally, the constants which have been calculated by means of the 



1 

 formula —l- 



- — for different HCl-concentrations, point to a more 



t .v^ — x 



rapid increase oi k-\-k' with the HCl-concentration than that required 

 by simple proportionality: 



1) The product obtained was syrupy and crystallised very slowly. Apparently, 

 a little ethylacetal or ethylglucoside must have been formed. 



