310 



STATE HORTICULTURAL SOCIETY. 



In the report of the Maryland experiment station for 1889, p. 67, are the 

 results of the determinations of sugar in 65 varieties, the percentage rang- 

 ing from 1.76 to 3.52; one variety gave 7.00 per cent. The determinations 

 were made in the aqueous extract directly, with Fehling's solution used 

 acording to the volumetric method. In the report of this station for 1891, 

 from 3.89 to 5.12 per cent, of sugar is reported, as obtained by H. Snyder 

 on eight samples; in these determinations the extract was examined by the 

 polariscope. Two analyses by Italian chemists gave respectively, 1.74 and 

 3.7 per cent. 



In the case of nearly half of the analyses made at the Maryland experi- 

 ment station the sum of the percentages of ash, sugar and malic acid 

 exceeds the total per cent, of dry substance; it is thus indicated that some 

 of these determinations of the constituents of the dry substance are too 

 high; and as other substances besides these three are in all probability 

 present in this dry substance, the error is even greater than thus 

 indicated. 



Some study has been devoted to the method of determining sugar in 

 this fruit, and the matter is still under investigation. The following is 

 given as a preliminary report only. 



It was hoped that the fermentation method could be applied; but as 

 results even on samples of pure glucose were unsatisfactory, its use was 

 given up. For all the determinations reported below, the fruit was dried 

 at 100°, the dry residue was powdered, and then extracted for the sugar 

 by boiling water when this was the extracting agent used, or by 90 per 

 cent, alcohol in the apparatus used in this laboratory for continuous extrac- 

 tion of fat by ether. The aqueous extract was so dark colored that a vol- 

 umetric determination by the Fehling solution could not be made; the 

 alcoholic extract was much less highly colored. This solvent was used in 

 hope that it might extract less of other reducing substances than sugar, 

 than water would take up. The gravimetric method, in which the copper 

 reduced from the cuprous oxide by hyrogen was weighed, gave very satis- 

 factory results. 



The results obtained are given in the following table: 



The acidity was determined by means of a standard solution of potas- 

 sium hydroxide, and calculated as malic acid. It seems certain that the 

 volumetric results were too low. The gravimetric results were obtained 

 with the alcoholic extract; duplicate results on the same extract agreed 

 closely. It will be noticed that one very low result on sugar in sample 6, 

 was accompanied by a very high per cent, of acid. 



G. C. CALDWELL. 



