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THE AMERICAN NATURALIST [Vol. XL VI II 



Conditions favoring rank growth result in coarse texture, 

 as was observed in several instances in the case of apples 

 grown under irrigation, especially if the fruit was over- 

 grown. Some of the fruit from young trees also was 

 overgrown and coarse. Tenderness depends upon the de- 

 velopment. Poorly grown, under-developed fruit grown 

 where the temperature is too low or the season too short 

 for the variety has hard flesh which becomes spongy 

 rather than mellow toward the end of the storage season. 

 Overgrown fruit of certain varieties, on the other hand, 

 often shows lack of coherence between the cells, often ac- 

 companied apparently by larger intercellular spaces, and 

 such fruit tends to become mealy as the season pro- 

 gresses. Juiciness is primarily a manifestation of the 

 amount of moisture in the fruit, but is also associated 

 with the tenderness of the cell walls and their tendency 

 to break rather than to separate. Tn general an abun- 

 dance of moisture results in juicy fruit though the juici- 

 ness is not in proportion to the moisture supply. The sub- 

 stances which give the apple its aroma are present in 

 such small amounts that their investigation is difficult. 

 They are volatile compounds and affect the flavor of the 

 apple largely by their action on the sense of smell. A 

 cool climate is favorable to their production and it was 

 often observed that they were most strongly developed in 

 the apples from elevated situations. Flavor depends 

 upon the kinds, amounts and relative proportions of the 

 soluble solids, especially the balance between sugars and 

 acids, antl will be given further consideration in the dis- 

 cussion of the chemical composition. Immature and 

 under-developed apples contain some tannic acid, w 

 is often sufficient in amount to give an astringent char 

 ter to the fruit. 



Keeping Quality. — In its relation to the environment, 

 keeping quality evidently follows the same rule as other 

 variable characters of the apple, namely, that for any 

 variety the keeping quality depends upon the optimum 

 intensity of the various external factors. Apples grown 

 where the temperature is too low or the season too short 



