1909.] Yeast-juice from Hexose and Phosphate. 535 



a separate quantity with magnesium citrate mixture. In Table III, already 

 given, Nos. 5, 6, 12, and 14 refer to acids prepared in this way, and it will be 

 seen that they cannot be distinguished from those which had undergone the 

 alkaline treatment. On hydrolysis, also, the same lsevorotatory solution 

 was obtained as is shown in Table VII. 



Table VII. 



No. 



Origin. 



Time of boiling, 

 in hours. 



Rotation in 



Before. 

 + 



4-drn. tube. 

 After boiling. 



1 



Glucose 



11 







0-056 



o 



-363 



2 





8 



0-131 



0-370 



3 



Fructose 



6 



0-637 



1 -184 



4 



2 



0-317 



0-276 







4 





0-574 







6 



)) 



0-956 







8 





1 -212 



(b) Nature of the Reducing Substance. — To determine the nature of this 

 reducing substance, the mixture from the hydrolysis of a preparation from 

 glucose was exactly neutralised to litmus with barium hydrate, and the 

 precipitation of the barium salts of phosphoric and unchanged hexdse- 

 phosphoric acids completed by the addition of two volumes of absolute 

 alcohol. After filtration, the solution was evaporated at 35° to 40° under 

 reduced pressure to a thick syrup. This was found to reduce Fehling's 

 solution in the cold, and to be lsevorotatory. It gave the red coloration 

 characteristic of fructose when heated with resorcinol and hydrochloric acid 

 (Seliwanoff). When this syrup was treated at 0° with milk of lime, an, 

 insoluble calcium compound similar to calcium fructosate was formed. This 

 was filtered off, washed with water, suspended in water, and decomposed 

 with carbon dioxide, and the filtered liquid treated with animal charcoal and 

 evaporated under reduced pressure. 



The colourless syrup thus obtained reduced an alkaline solution of copper 

 glycocolate after 12 hours in the cold, a reaction which, according to Pieraerts,* 

 is only given by fructose. It readily formed an osazone when heated with 

 phenylhydrazine in the usual manner, and this, after recrystallisation, first 

 from alcohol and then from a mixture of pyridine and water, melted at the 

 same temperature as glucosazone, viz., 206°, whilst a mixture of this compound 



* ' Chem. Zentral.,' 1908, vol. 1, p. 1854. 



2 Q 2 



