12 STUDIES ON APPLES. 
(glucose) formed from starch by the action of acids was found by Biot 
to be not the same as the sugar in fruits. 
Some of the ideas of Frémy were vigorously combated by Cou- 
verchel.“ , 
A-very valuable contribution to the subject of the analysis of fruits 
by Buignet,’ which appeared in 1860, is of interest because of the 
methods given for the determination of many constituents of the straw- 
berry. Water, acid, sugars, fat, soluble and insoluble protein, mare, 
nitrogen-free parenchyma, pectin, odoriferous principles, coloring 
matters, and ash are worked out. Strawberries containing the least 
water are said to contain the most sucrose, and this is explained on 
the hypothesis that the acid and sucrose are contained in different cells, 
and in the presence of much water these diffuse more readily than in 
drier berries, a more rapid inversion ensuing. Sucrose is believed to 
be the initial sugar formed. Results for many varieties of strawber- 
ries are tabulated. A later paper’ gives results concerning sugars 
in fruit in the form of a summary of 14 conclusions, some of which 
are as follows: Sucrose is found in many fruits, becoming inverted in 
the ripening, sometimes completely, e. g@., in grapes, currants, and 
figs: sometimes partially, e. g., in bananas, apricots, peaches, plums, 
apples, and pears. No relation exists between sucrose and the acidity 
of fruits, but the sugar is probably inverted by a nitrogenous ferment. 
This was proved by showing that, after precipitating with alcohol, the 
sucrose remained unchanged; that after neutralizing an original sample 
of juice with calcium carbonate, the inversion still went on; and that 
in bananas, which have no free acid, starch is rapidly changed to 
sucrose. Invert sugar prevents the crystallization of sucrose, but the 
latter sugar was isolated in crystals from a number of fruits by a pro- 
cedure which is described. Starch was not found in fruits (except the 
banana), but a tannin-like, astringent principle is described as oceur- 
ring in unripe fruits, which decolors an iodin solution, yielding a pre- 
cipitate which, when treated with acid, yields a glucose sugar, the same 
as that formed from nut galls. The starch and tannin found in the 
banana are said to disappear simultaneously, giving rise to cane sugar. 
Finally we are told that a difference exists between sugars of fruits 
according as they are produced under action of vegetable forces, or 
Without it, e. g., bananas contain more sucrose and less invert sugar 
when allowed to ripen on the tree than if ripened after picking. 
Berthelot and Buignet” worked on the ripening of oranges. Two 
samples of green oranges were studied. Several fruits from each 
“Compt. rend., 1844, 19: 1) 14. 
’J. pharm. chim., 1859 (3), 86: 81-111 and 170-198; résumé in Compt. rend., 
1859, 49: 276-278. 
¢Compt. rend., 1860, 41: 894. 
@[bid.: 1094. 
