358 THE MONTHLY BULLETIN. 



Now a fruit is rightly ripe only when it is brought to its fullest 

 maturity. But there are no well marked lines between greenness, 

 maturity and decay. These stages grade insensibly into each other, 

 but coloring, it is well to remember, continues up to the point at 

 which the tissues begin to decay. Shakespeare might have had the 

 ripening and coloring of fruits in mind when he wrote : 



"And so, from hour to hour, we ripe and ripe. 

 And then, from hour to hour, we rot and rot." 



Coming as quickly as possible to practical applications of all this, 

 we have at once to call your attention to the fact that the coloring 

 of fruits is largely a chemical process and that chemical processes 

 are profoundly influenced by the conditions under which they take 

 place. Chief of these in influencing color formation in plants are 

 light and heat, but there are others, as food, or lack of it, moisture, 

 chemicals in the soil and disease. 



Every fruit-grower knows that the intensity of color in fruits 

 depends largely on the amount of light. Like the complexion of 

 Shakespeare's dusky Moor, the color of fruit is often "but the bur- 

 nished rays of the burning sun." Poorly colored fruits are often due 

 to close planting and density of treetop, whereby sunlight is excluded. 

 Light largely determines the rate and the amount of oxidation that 

 takes place in plant cells and bright light makes all color-production 

 processes active. The effects of an abundance of light in producing 

 high color are to be seen in top branches, in open-centered trees, in 

 outside and wide apart rows and in the products of the sunlit states 

 of the west or the high altitudes of any fruit growing region. Of the 

 few means at the command of the fruit grower to obtain better color 

 those having to do with securing more light are most efficient — as 

 pruning, greater distance apart of trees and in selecting sites best 

 exposed to the sun. 



Not only does light from the sun influence the amount of color in 

 fruits, but solar heat has its effect. One who has not given the matter 

 thought immediately jumps to the conclusion that the warmer the 

 weather the brighter the colors, whereas the contrary is usually the 

 case. We found from records of twenty-five harvests in New York 

 that apples usually colored especially well in falls when they ripened 

 in cool weather, more particularly so if the nights were cool and the 

 days bright and sunny. Indeed, saving numerous "just exceptions 

 and reservations," it is not too much to say that rainy weather, by 

 lowering the temperature, especially if it alternates with sunshine, 

 may help to give high color to fruit. 



The effects of low temperature on color may well be seen in northern 

 climates, and high altitudes where colors are always brighter than in 

 warm climates or low altitudes. The cool nights of the Pacific North- 

 west are nearly as potent as the sunny days in giving color to the 

 fruits of that region. There is a plausible reason for the effects just 

 ascribed to cool weather in influencing color. The chemical changes 

 which bring about color in fruit accompany the period of ripening. 

 Now ripening marks the cessation of cell activities — comes with the 

 death of cells. In fact, color pigments may almost be said to be waste 

 products— the "ashes of the vital fires" of cells. Cold hastens the 

 death of the cell, the ripening of the fruit and so increases color. 



