RIPENING OF FRUITS. 271 



Water. Sugar. Cellulose. 



Unripe. Ripe. Unripe. Ripe. Unripe. Ripe. 



Apricot 89-39 74'87 .. 6'64 16'48 .. 3'61 1'86 



Peach 90-31 80-24 



Cherries 88'28 74-85 



Plums 74-87 71-10 



Pears 86-28 83'88 



0-63 11-61 



1-12 18-12 



17-71 24-81 



6-45 11-52 



3.01 1-21 



2-44 1-12 



126 1-11 



3-80 2-19 



567. It is not easy in all cases to determine the exact time when 

 the fruit is ripe. In dry fruits, the period immediately before dehis- 

 cence is considered as that of maturation ; but, in pulpy fruits, there 

 is much uncertainty. It is usual to say that edible fruts are ripe, when 

 their ingredients are in such a state of combination as to give the most 

 agreeable flavour. This occurs at different periods hi different fruits. 

 After succulent fruits are ripe in the ordinary sense, so as to be capable 

 of being used for food, they undergo further changes, by the oxidation 

 of their tissues, even after being separated from the plant. In some 

 cases, these changes improve the quality of the fruit, as in the case of 

 the Medlar, the austerity of which is thus still further diminished. In 

 the Pear, this process, called by Lindley bletting (from the French, 

 blessi), renders it soft, but still fit for food ; while in the Apple, it 

 causes a decay which acts injuriously on its qualities. By this process 

 of oxidation, the whole fruit is ultimately reduced to a putrefactive 

 mass, which probably acts beneficially in promoting the germination 

 of the seeds when the fruit drops on the ground. 



568. The period of time required for ripening the fruit, varies in 

 different plants. Most plants ripen their fruit within a year from the 

 time of the expansion of the flower. Some come to maturity in a few 

 days, others require some months. Certain plants, as some Conifera?, 

 require more than a year, and in the Metrosideros, the fruit remains 

 attached to the branch for several years. The following is a general 

 statement of the usual tune required for the maturation of different 

 kinds of fruit : 



Grasses 13 to 45 days 



Raspberry, Strawberry, Cherry ....2 months. 



Bird-cherry, Lime-tree 3 



Eoses, White-thorn, Horse-chestnut 4 



Vine, Pear, Apple, Walnut, Beech, Plum, Nut, Almond, 5 to 6 



Olive, Savin 7 



Colchicum, Misletoe 8 to 9 



Many Coniferae, 10 to 12 



Some Coniferag, certain species of Oak, Metrosideros, above 1 2 



The ripening of fruits may be accelerated by the application of heat, 

 by placing dark-coloured bricks below it, and by removing a ring of 

 bark so as to lead to an accumulation of sap. Trees are sometimes 

 made to produce fruit, by checking their roots when too luxuriant, 

 and by preventing the excessive development of branches. 



