1913. 



PUBLIC DOCUMENT — No. 31. 



165 



The writer has found the composition of the combined crowns 



and roots in his samples to averag'e as follows: — 



November, 



1908, 

 16 Roots. 



November, 



1910, 



4 Roots. 



June, 1911, 

 8 Roots. 



Dry matter. 



Ash 



Crude protein, . 

 Crude fiber. 

 Fat, . . . . 

 Nitrogeu-free extract. 



Sugar, 

 Pentosans, 



6.24 

 11.03 

 15.39 



1.00 

 66.34 



100.00 



41.43 



8.78 



22.40 

 7.68 



11.02 



17.89 

 1.58 



61.83 



100.00 



35.85 

 10.12 



18.34 



8.87 

 12.75 

 23.60 



1.63 

 53.09 



100.00 



20.87 

 11.66 



The sugar which forms such an important percentage of the 

 reserve material has been found to be a soluble carbohydrate 

 readily hydrolyzed to glucose and fructose, having a rotary 

 power differing widely from cane sugar, but otherwise resem- 

 bling it in all its chemical properties.^ 



In the series of 1910 and that of 1911 particular attention 

 was paid to the sugar to determine if fertilizers had any effect 

 on its development. 



The sugar was extracted by heating 2 grams of the dry, finely 

 powdered material with 50 cubic centimeters of water in the 

 boiling water bath. Basic lead acetate and alumina cream were 

 added after the solution was cool, and the volume made up to 

 100 cubic centimeters. When the precipitate had settled, which 

 it usually did in an hour, the solution was filtered through a 

 dry filter. The lead was then removed with sodium carbonate 

 and an aliquot of 50 cubic centimeters was inverted by HCl by 

 standing for twenty-four hours at 20° to 25° C. 



About half of the samples showed the presence of reducing 

 sugars before inversion, but seldom more than a trace ; the 

 remainder showed no presence of reducing sugars 



The total invert-sugar was determined by use of Fehling's 

 solution in the usual manner, and the copper was deteraained 

 volumetricallv. 



• Tanret, loc. cit.; Wichers and Tollens, loc. cit.; Morse, Jour. Am. Chem. Soc., 33, 211-215. 



