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 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 the} 7 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 c 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 



-77^, are the chief criteria used. The fruit (a single fruit in case of 

 V 2 



apples) is held in a sealed glass container, and the air of the chamber 

 is analyzed after a 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 rapidty than ripe apples. The respiratory 



CO 

 quotient, ^y^, 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 i. e., ripen- 

 ing after picking because here no sap is added to the fruit. Apples 



Centrbl. agrikultnrchem. (Biedermann), 1902, 31: p. 104. 

 &Landw. Versuchs-Stat., 1902, 56: 427. 

 ^Loc. cit. (see p. 9). 



