ACTION OF LEAVES ON. FRUIT. 99 



surrounding parts ; and we see that this property causes the 

 destruction of some fruits by their neighbours which are more 

 advanced in growth, or accidentally more vigorous, and whose 

 attracting power is so great as to draw to themselves all the food 

 intended for the weaker fruits, which then fall off. Of the food 

 thus to be consumed in the maturation of the fruit, a portion 

 is derived from the atmosphere, but the principal part has to 

 be prepared by the leaves, which obtain it in a great measure 

 from the earth through the roots. It is, therefore, evident, 

 that all causes, of whatever nature, which interfere with the 

 healthy and regular action of the leaves and roots will also 

 interfere with the fruit. Or, if the leaves are placed in such a 

 manner with respect to the fruit, or at so great a distance from 

 it, that the fruit is unable to attract food from them, it must 

 either suffer or perish. 'This explains why fruit formed upon 

 naked branches will not continue to grow, and why the presence 

 of a leaf immediately above a fruit, on the same branch, is so 

 beneficial to it. The size and excellence of fruit will hence be 

 in proportion to the abundance of organizable matter prepared 

 and stored up in its vicinity.* 



It occasionally happens that stone-fruit will swell upon naked 

 branches ; but such cases are exceptional, and probably depend upon 

 circumstances unrecorded by those who have observed them. It has 

 been admitted that, in some instances, such fruit has been altogether 

 deficient in flavour ; though in others it is said to have been otherwise. 

 See the Gardener's Chronicle for 1842, p. 588, and for 1843, pp. 43 and 

 115. 



* The accumulation of sap, and its consequent viscidity, may, ho-weTer, be 

 attended witli disadTantage to a plant, aa really happens in the Potato, the most 

 farinaceous varieties of which are liahle to a disease called the "curl." Mr. Enight 

 attributed this to the inspissated state of the sap, which, he conceived, if not 

 sufficiently fluid, might stagnate in and close the fine vessels of the leaf during its 

 growth and extension, and thus occasion the irregular contractions which constitute 

 this disease. He therefore sufiered a quantity of Potatoes, the produce almost whoUy 

 of diseased plants, to remain in the heap, where they had been preserved during 

 winter, tiU each tuber had emitted shoots of three or four inches in length. These 

 were then carefully detached, with their fibrous roots, from the tubers, and were com- 

 mitted to the soil, when, having little to subsist upon except water, not a single 

 cm-led leaf was produced, though more than nine-tenths of the plants which these 

 identical tubers subsequently produced were much diseased. The same effect has 

 been produced by other persons, by taking up the tubers intended for seed before 

 they were full grown, and, consequently, before the excessive inspissation of their 

 secretions had taken place. 



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