1909.] Yeast-juice from Hexose and Phosphate. 531 



given in Table I. The mannose employed was obtained by the hydrolysis of 

 ivory-nut, and was purified by being converted into the phenylhydrazone, 

 which was recrystallised from water and decomposed with benzaldehyde. 



Table I. 



No. 



Origin of 

 compound. 



Weight 

 taken. 



C0 3 . 



H 2 0. 



Mg 2 P 2 7 . 



PbS0 4 . 



C. 



Percer 

 H. 



itages. 

 P. 



Pb. 



1 



Glucose ... 



-5261 



-1870 



-0777 







9-69 



1-65 











-6269 







-1775 



-5080 







7-88 



55 -34 



2 





"4745 



-1696 



-0732 







9-75 



1-73 











-5993 







-1704 



-4774 







7-92 



54 -40 



3 



Fructose ... 



-3040 







-0890 



-2484 







8-15 



55 -81 



4 



,, ... 



-4503 







-1337 



-3649 







8-27 



55 -34 



5 



Mannose . . . 



-3614 







-1021 



-2931 







7-87 



55 "39 



C 6 Hi O 4 (PO 4 Pb)., requires 



9-60 



1-33 



8-27 



55 -20 



Hexosephosphoric acid was obtained from the lead salt by suspending it in 

 water, decomposing with sulphuretted hydrogen, and removing the excess of 

 this gas from the filtered liquid by means of a current of air. An acid 

 liquid was thus obtained which could be titrated with standard alkali, 

 phenolphthalein being used as indicator, in a similar manner to phosphoric 

 acid. In Table II several examples are given in which the amount of 

 hexosephosphoric acid was estimated both by titrating the solution with 

 decinormal alkali, and by decomposing with nitric and sulphuric acids, 

 precipitating with magnesium citrate mixture, and weighing as magnesium 

 pyrophosphate. The numbers all refer to 10 c.c. of the solutions. 



Table II. 



Origin. 



Titration, 

 c.c. N/10. 



MgoP.O;. 



Hexosephosphoric acid. 

 From titration. From Mg 2 P 2 O r . 





19 -8 



-1086 



-1683 



-1664 





63 -4 



-3458 



-5390 



-5296 





99 -0 



-5434 



-8415 



-8323 





9-6 



-0517 



'0816 



-0792 





29 -2 



-1559 



-2482 



-2388 





38 -7 



-2124 



-3290 



-3253 





32 -6 



-1802 



-2771 



-2761 



When the solution was evaporated on the water-bath a charred mass was 

 left which contained free phosphoric acid and had a strong odour of caramel, 

 whilst even on evaporation under reduced pressure, or at ordinary tempera- 



