STORAGE, RESPIRATION, AND GROWTH. 19 



were examined during this period. The influence of temperature, 

 quantity of acid present in the fruit, variety of apple, and the effect 

 of quartering the apples on the intensity of respiration and on the 

 respiratory quotient are described. Apples respire more rapidly at 

 30 and at 33 than at 18 C. Apples relatively high in acid respire 

 more rapidly and have a higher respiratory quotient than apples low 

 in acid. The influence of cutting the apple into quarters is to increase 

 the intensity of respiration and respiratory quotient. 



Similar researches were carried out with grapes, citrus fruits, 

 almonds, peaches, plums, and apricots. The existence of a respira- 

 tory quotient greater than unity due to the combustion of acids is 

 considered by the author to be established, and numerous conclusions 

 concerning the effect of various factors on the function are given. 



Work with molds is described, the respiratory quotient of these 

 organisms growing on different media being determined, and the 

 results are believed to furnish direct support to the conclusions 

 which the author has drawn from his work with fruits. 



Other fruits, Japanese persimmons (Diospyrus kakizendji), bananas, 

 sorbes (Sorkus domestica), and medlars (Mespilus germanicaj were now 

 examined by the method of the author. In persimmons tannin is 

 believed to disappear by direct combustion, with no formation of 

 sugar, this conclusion, however, depending on the results of an analy- 

 sis of a single persimmon. 



The conclusion reached with the acid fruits, that the combustion of 

 the acids is reponsible for the excess of carbon dioxid given off over 

 oxygen consumed, possesses a certain probability merely because of the 

 uniformity of the results obtained with a wide range of varieties of acid 

 fruit. Gerber's work is valuable as suggesting certain auxiliary work 

 that may be carried on in connection with the chemical work necessary 

 to the study of the ripening of fruit. His theories should be considered 

 as hypotheses which must be confirmed by suitable scientific methods 

 before they can be seriously regarded. Such data should be consid- 

 ered as indications of facts only. The number of individual speci- 

 mens in the samples examined and the methods employed do not 

 warrant that any greater weight be given to the data. At the same 

 time it is shown that the examination of the respiratory changes in 

 fruits is easily made, and that fruits of different varieties and different 

 degrees of maturity vai^ materially in the intensity of their respira- 

 tion. The method would probably be of value in supplementing 

 chemical work on growing or ripening fruits. 



From the above review it will be recognized how varied are the 

 conclusions reached by workers with ripening fruits. With better 

 chemical knowledge, particularly concerning sugars and starch, satis- 

 factory agreements are found between the work of various modern 

 authors working with apples and grapes. It must be considered that 



