18 STUDIES ON APPLES. 
studied the growth and ripening of a variety of apples, noting that 
the percentage of water, acid, and starch decreased more or less 
uniformly, while dry matter, extract, sucrose, and reducing sugar 
increased. In another contribution by Otto” a study of the changes 
which go on in common storage is presented. Samples of eight varie- 
ties of apples were analyzed before and after cellar storage. A gradual 
diminution of all constituents was found except in two cases in which, 
while the acid and starch decreased, the total sugar showed a slight 
increase. 
In further work done by Otto? it was found that the starch in ripe 
apples when they were allowed to sweat in piles was entirely converted 
into sugar in two or three weeks, the fruit thus becoming more valua- 
ble for cider making. 
The contribution of Gerber“ to the subject of the ripening of fruits 
is of considerable importance. The work is of some length, occupying 
280 pages. First, the work of various writers on respiration and car- 
bohydrate, acid, and tannin changes in growing and ripening fruits is 
reviewed, together with the resulting hypotheses regarding these 
functions. The author then describes the methods and apparatus 
employed by him in the researches which are described. The relative 
intensity of respiration and the value of the respiratory quotient, 
CO, RON sath ep : yey, Hos: 
“©, > are the chief criteria used. ‘The fruit (a single fruit in case of 
apples) is held in a sealed glass container, and the air of the chamber 
is analyzed aftera time. The air is then renewed and the experiment 
repeated, the temperature being held constant. In this way the inten- 
sity of respiration and the respiratory quotient—i. e., the ratio of 
carbon dioxid given off by the fruit to the oxygen consumed—may be 
observed. 
The method is first employed with apples. It is noted that unripe 
apples breathe much more rapidly than ripe apples. The respiratory 
\ 
quotient, ~¢ *, is found to be greater than unity in the case of growing 
apples, but it is considered that it is impossible to determine to what 
constituent this fact is due, because, although the constituent, malic 
acid—which is suspected of furnishing the extra carbon dioxid— 
decreases relatively to the other constituents (though increasing in 
absolute quantity) during growth, it is impossible to determine whether 
or not the sap which is supplied to the apple varies in composition 
during the period of growth. More definite results are considered to 
be obtained with apples during the period of after-ripening—1. e., ripen- 
ing after picking—because here no sap is added to the fruit. Apples 
“Centrbl. agrikulturchem, (Biedermann), 1902, 31: p. 104. 
bLandw. Versuchs-Stat., 1902, 56: 427. 
¢ Loc. cit. (see p. 9). 
