168 Mr. E. H. Acton. Ike Assimilation of Carbon 



cylinder containing 100 c.c. of the culture solution + 0"5 gram 

 saccharon. 



The two cylinders were placed under the same bell-jar and arranged 

 so as to be as nearly as possible illuminated to the same extent. 



After three days (the leaves of (a) and (JB) then containing starch) 

 I determined the remaining glucose and saccharon in the cylinders by 

 making up to an equal volume in each case and withdrawing an 

 aliquot part for analysis. 



Of the glucose 0"237 gram remained (absorbed 0*263 gram). 



Of the saccharon 0'302 gram remained (absorbed 0"198 gram). 



This experiment was confirmed by arranging another six plants in 

 a similar manner and testing each day how much of the glucose 

 and saccharon had been removed during the preceding twenty-four 

 hours. 



Commencing on the second day after placing the cylinders in the 

 bell-jar, it was found at the beginning of the third day that — 



(2nd to 3rd day), in 24 hours, 0*085 gram glucose, 0'061 gram 

 saccharon. 



(3rd to 4th day), in 24 hours, 0'074 gram glucose, 0'062 gram 

 saccharon. 



I therefore conclude that glucose is more readily taken up by the 

 roots of plants (from 5 per cent, solutions) than saccharon.* 



No. 8. Experiments with " Dextrins" 



The dextrins used were of two kinds : — 1. Erythro-dextrin ; 2. 

 A chroo- dextrin. 



Erythro-dextrin used was obtained as " dextrin " in dry state from 

 Messrs. Hopkin and Williams, of London. It was well washed with 

 strong alcohol before solution in water, to remove any traces of 

 glucose. 



The achroo- dextrin was prepared from the above by heating with 

 5 per cent. H 3 S0 4 on a " calcium chloride bath" (temperature above 

 100°) till the solution, neutralised with BaC0 3 , gave no trace of reac- 

 tion with I in KI. 



The dextrin was then precipitated by the addition of strong (95 

 per cent.) alcohol and washed with the same until the washings were 

 perfectly free from "reducing" substances, dried, and dissolved in 

 water. 



* This result is not in keeping with the experiences of A. Meyer as to the rela- 

 tive value of glucose and saccharon. "When leaves are placed in 10 per cent, 

 solutions he finds starch to be more readily formed from saccharon than dextrose 

 (glucose). I have r.ot experimented with " lsevulose." 



