( 606 ) 



From sexeml experiments I have made, 1 tliiiik the conclusion 

 maj be drawn that it is probable that saccharose niav be rege- 

 nerated to a slight extent from glucose and fructose l\y means 

 of invertase, whilst it may be taken as proved with tolerable 

 certainty that salicin ma}- be regenerated from saligenin and glucose 

 by means of emidsin. 



If, with the usual precautions, a N/^ solution of saccharose ^) is 

 exposed to the action of in\'ertase, the former is resolved into 

 glucose -|~ ft'iictose and the liquid shows a tinal polarisation 

 of — 3°.26 '). 



If a similar solution is inverted by N/„ HCl the linal polarisation 

 becomes — 3°. 42. 



A solution containing the same amount of glucose and fructose') 

 as is formed after total inversion of a N/^ solution of saccharose 

 also gives a final polarisation of — 3°.42. 



A solution conlaining equal quantities of glucose -\- fructose and 

 which showed at the start a })olarisalion of — 'J2°.46 gave after 

 two months action of invertase a polarisation of — 12^.29. These 

 experiments have been repeated a few times. 



A N/i8 solution of salicin, resolved by emulsin iiilo saligenin and 

 glucose, gave a final polarisation of 1'^. 03 whilst a solution containing 

 as much saligenin and glucose as ought to be formed by the 

 complete decomposition of a N',„ solution of salicin shows a polari- 

 sation of 1°.J8. Such a solution which contains the same amount 

 of emulsin as the N/'m solution of salicin gave after a month 

 a polarisation of I''. 03. 



The formation of salicin, which siiows that the reaction is 

 reversible, may be proved qualitatively in the followiiig manner. 

 The glucose was got rid of as much as possible l)y fermentation 

 and after filtering, the saligenin was conq>letely removed by agitating 

 the solutioji with ether. The litpiid was now concentrated to about 

 5 c.c. on the waterbath. To ojie half of it was added a drop of 

 ferricchloride solution (1 : 10); this gave no coloration showing the 

 absence of saligenin, a mere trace of which woidd give a blue 

 coloj'ation. The remainder was evajtoraled to dryness and gave 

 with Hg SO4 a i-ed coloration (fornuitiou of rutilin). 0.5 c.c. of a 1 "/o 



1) All solutions mentioned contained 0.5 % of sodium fluoiide to prevent 

 bacterial action: all apparatus and utensils were also previously sterilised. 



2) A Lippich-polariraeter was u«ed. The readings were accurate up to 0°.02 

 and all observations were made at i2.j^. 



8) I have to thank Mr. Alberda van Ekenstein for supplying me with these 

 perfectly pure sugars. 



