318 



Prof. R. W. Atkinson. 



The percentage composition, calculated as before, is 



Maltose 71*54 



Dextrin.. 28*46 



100*00 



and calculated the specific rotatory power is /o=168°*8. 



With a solution prepared from different Jcoji, using 50 cub. centims.. 

 containing '603 grm. of solid matter, the following results were 

 obtained from 5 grms. of gelatinised starch kept for two hours at 10° 

 to 15° C. 



Maltose 70-00 



Dextrin 30'00 



100-00 



P (observed) =174°'0 



P (calculated) =169° '8 



The two last results correspond with Brown and Heron's equation 

 No. 7. 



10C 13 H 20 O 10 + 7H 2 = 7C 12 H 22 O n + 3C 13 H 20 O 10 , 



which requires 70*9 per cent, maltose, and />=169°-2. 



An example may now be given of a solution containing both maltose 

 and dextrose. 



5 grms. of gelatinised starch were mixed with 56 cub. centims. of 

 Icoji extract, the same as in the last experiment, and allowed to stand 

 at a temperature of from 10° to 15° C. for twenty- four hours. After 

 diluting to 250 cub. centims., and making deductions for the Tcoji 

 added, the composition of the solid matter was — 



Maltose 52*8 per cent. 



Dextrose 2379 „ 



Dextrin 23-41 



100-00 „ 



P (observed) =143°-8 



P (calculated) =143°'8. 



It may be observed, that the number of molecules of each body pre- 

 sent is very nearly the same — a mixture of one molecule of maltose, 

 one of dextrose, and one of dextrin, requiring 



Maltose 50*00 per cent. 



Dextrose 26-30 



Dextrin 23' 70 



100*00 



and p=141°*7. 



