698 REPORT — 1891, 



showing, it is not one wliich can give satisfactory results ; lie preferred the more 

 laborious but more definite method of determining the sugar present by means of 

 standard Fehling's solution. This method involved careful preparation of the 

 liquids to be tested, so that they should be quite clear and colourless. At the close 

 of the period of digestion, the liquid was neutralised with lime-water, and then 

 boiled and filtered through 5 grammes of recently ignited animal charcoal until all 

 the colour was removed ; the charcoal was well washed, the washings being added 

 to the filtrate, which was then made up to standard volume, when it was ready for 

 the determination of sugar. The liquids belonging to each experiment were all 

 simultaneously treated in precisely the same manner. The determination of sugar 

 was effected by allowing the liquid to drop from a graduated burette into a fixed 

 quantity of boiling standard Fehling's solution, continuing the boiling for three 

 minutes. The purity and the uniform strength of the Fehling's solution were 

 carefully attended to. The amount of the reducing substance was, in all cases, 

 calculated as dextrose. 



In order to determine whether or not the substance in the liquids which reduced 

 Fehling's solution really was sugar, a quantity of leaf-extract was made, filtered, and 

 dialysed : the resulting clear solution evaporated to dryness. A residue was thus 

 obtained which smelt strongly of sugar, and which dissolved readily in water ; the 

 strong watery solution of the substance gave a well-marked reaction with sodium 

 acetate and phenyl-hydrazine hydrochloride, a reddish-yellow precipitate being 

 formed on warming, consisting of tufts of large acicular crystals. The solution did 

 not, however, have any rotatory effect on polarised light when examined in the 

 polarimeter. There can be no doubt that the substance is a sugar, and presumably 

 it should be maltose ; but it does not resemble maltose in being strongly dextro- 

 rotatory. In order to determine whether or not it is capable of undergoing 

 alcoholic fermentation, some yeast (10 c.c.) was added to some of the pure sugar- 

 solution (100 c.c.) and the mixture was kept for twenty-six hours in an mcubator 

 at about 36° C. It appeared to be fermenting, and when distilled, a liquid came 

 over of sp. gr. •997, which would correspond to about 2 per cent, of alcohol : this 

 liquid also gave the iodoform reaction. The sugar in question appears, therefore, 

 to be fermentable. 



A further peculiarity, which may be of some importance, is that the crystals of 

 the phenyl-compound produced in the phenyl-hydrazine hydrochloride test are 

 soluble in absolute alcohol, giving an orange-coloured solution, but they are almost 

 insoluble in ether ; whereas the crystals formed (phenylglucosazone) when dextrose 

 is similarly treated are readily soluble in both alcohol and ether, giving a yellow 

 solution. 



The sample of the sugar above described was obtained from a mixture of 

 800 c.c. of leaf-extract (prepared from 750 grammes fresh lawn-mowings con- 

 sisting chiefly of grass, with some clover and Achillea) with 900 c.c. starch- 

 solution. The sugar obtained included that which was originally present in the 

 leaf-extract, as well as what was formed from the added starch. 



The following will serve as an example of the experiments, and of the results 

 obtained : — Six flasks were prepared, and were allowed to stand overnight for 

 14i hours : the leaf-e.xtract was prepared from fresh lawn-mowings. 



Dextrose 

 c.c. c.c. per cent. 



No. 1.— 50 leaf -extract -i- 50 starch-solution gave -0793 



„ 2.— 50 „ (J)oiled) + b(i „ , "0450 



„ 3.— 50 „ -f50 „ -H thymol . . . „ •0740 



., 4. — 50 „ +50 „ + boiacic acid | grm. „ -0690 



„ 5.— 50 „ + 50 distilled water „ -0440 



„ 6. — 50 starch-solution -f 50 „ „ „ none 



The sugar was estimated as fractions of grammes of dextrose in 100 c.c. of 

 liquid. Similar results were obtained with leaf-extracts of the Marrow {Ciicwbita 

 ovifera), the Sunflower (Helianthus annuus), and the Dwarf Runner {Fhaseolus 

 vulgaris) ; also with those of the Lime (Tilia europcea) and of the Dwarf Runner 

 when a 1 per cent, solution of dextrin was used. 



