312 



Prof. R. W. Atkinson. 



the property of causing inversion of a solution of cane-sugar, as the 

 following experiments will show :— 



1*974 grm. of dry cane-sugar was dissolved in 25 cub. centims. of 

 koji extract, then diluted to 100 cub. centims. The amount of optical 

 rotation was found, by observation, to be 15*8 scale- divisions, and the 

 number calculated was 15*5. Thus — 



1*974 grm. cane-sugar dissolved in 100 cub. 



centims. would give rotation = 12*1 divisions. 



25 cub. centims. of koji solution diluted to 



100 cub. centims , = 3*4 „ 



15*5 „ 



After being allowed to stand for eighteen hours the rotation was ob- 

 served to have diminished to 5 scale-divisions, and the solution con- 

 tained 1*67 grm. of glucose. Deducting 0'36 grm. glucose contained 

 in 25 cub. centims. of koji solution, the amount formed from the cane- 

 sugar was 1*31 grm., equivalent to 1*2445 grm. cane-sugar ; and hence 

 0*7294 grm. of unaltered cane-sugar was present. We thus find the 

 calculated number of divisions of rotation to be +5*43, against 

 5 divisions actually observed. 



Unaltered cane-sugar (*7294 grm.) in 



100 cub. centims -|-4*4 scale divisions. 



Koji extract (25 cub. centims. in 100 



cub. centims.) +3*4 „ ,, 



Invert sugar formed (1*31 grm. in 



100 cub. centims.) -2*37 



+ 5*43 



If the calculation be made in degrees of arc, it will be found that the- 

 specific rotatory power of the solution had diminished from /> = 74° to 

 7>=10°. 



The progress of the inversion of the solution of cane-sugar will be 

 seen from the following observations taken at successive intervals of 

 time : — A solution of cane-sugar containing 5*41 grms. in 100 cub. 

 centims., and giving in a 200 millims. tube an optical rotation of 33*1 

 scale- divisions (equal to p = 74i°), was employed. 75 cub. centims. of 

 this solution Tvere mixed with 25 cub. centims. of a solution of koji 

 which contained 0*365 grm. of solid matter, 0*253 grm. glucose, and 

 which gave in a 200 millims. tube an optical rotation of 8 scale- 

 divisions. It may be remarked that from these and other experiments 

 made with the same solution of koji, it was found to be exceptionally 

 weak in its inverting power. The observations are as follows, deduc- 

 tion having been made for the koji solution present : — ■ 



