308 



Prof. E. W. Atkinson. 



cent, to 333 per cent. The percentage of glucose contained in the 

 solid matter varies from -45 to 68 per cent., but usually ranges 

 between 50 and 60 per cent. The specific rotatory power of the 

 solution made in the cold does not vary much outside the limits 

 60° and 70°. 



The solution contains dextrose, dextrin, and albuminoids, the two 

 latter in nearly equal amounts. In some solutions in which the 

 nitrogen dissolved was determined, the specific rotatory power of the 

 albuminoids was found to be — 40", and it will, probably, not be far 

 from the truth to take this number as the average specific rotatory 

 power of the albuminoids. 



Two points are brought out by a consideration of Table III. In 

 the first place the proportion of water used appears to influence con- 

 siderably the amount of solid matter brought into solution. The 

 average of the numbers obtained when 100 grms. of hoji were dissolved 

 in 1,000 cub. centims. is only 27, whilst when the same weight was 

 dissolved in 2,500 cub. centims. the average was 31*4. The single 

 experiments given also bear out this with the exception of No. 18 ; 

 but in a matter of this nature no reliance can be placed upon isolated 

 observations. The second point is that the specific rotatory power of 

 the solids in solution appears to be mainly influenced by the length of 

 the digestion, being much higher when the digestion is short than 

 when it is continued for some time. The average specific rotatory 

 power of the solutions made in eighteen hours was 57° "6 ; after twelve 

 hours. 61°*6 ; and after three hours, 69 = '3 ; although the last number 

 is not fairly comparable with the two former ones, a different propor- 

 tion of water having been used. The explanation of this fact is 

 probably that when the digestion is continued for only a short time, 

 a smaller proportion of albuminoids enters into solution than when 

 the digestion is long continued. It is probable, in fact, that the 

 albuminoids require time to be degraded to such a form that they 

 are soluble in water. Hence, when the amount of albuminoids is 

 small, the dextrose and dextrine mainly contribute to the specific 

 rotatory power, which is, therefore, higher. 



In Table IV are given a few results of experiments in which the 

 mixture of koji and water was heated fcr different periods. 



rotatory power (which I have expressed throughout the paper hy the symbol p) was 

 calculated from the formula — 



n x 0-242 

 Pi=— — — 

 2 x s 



where n is the number of divisions read off from the scale, 



0'242 is the factor for converting scale-divisions into degrees of arc (cane-sugar 



being taken =73~ , -8), 

 £ is the amount of solid matter in 1 cub. centim. of solution in crams. 



