162 FRUIT. 



224. Fruit is exclusively fed by the secretions prepared for 

 it by other parts ; it is therefore affected by nearly the same 

 circumstances as flowers. 



225. It will be large in proportion to the quantity of food 

 the stem can supply to it ; and small in proportion to the 

 inability of the stem to nourish it. 



226. For this reason, when trees are weak they should be 

 allowed to bear very little, if any, fruit; because a crop of 

 fruit can only tend to increase their debility. 



227. And in all cases each fruit should be so far separated 

 from all others as not to be robbed of its food by those in its 

 vicinity. 



228. "\Ve find that nature has herself in some measure provi- 

 ded against injury to plants by excessive fecundity, in giving 

 them a power of throwing off flowers, the fruit of which can- 

 not be supported. 



229. The flavour of fruit depends upon the existence of 

 certain secretions, especially of acid and sugar; flavour will, 

 consequently, be regulated by the circumstances under which 

 fruit is ripened. 



230. The ripening of fruit is the conversion of acid and other 

 substances into sugar. 



231. As the latter substance cannot be obtained at all in the 

 dark, is less abundant in fruit ripened in diffused light, and 

 most abundant in fruit exposed to the direct rays of the sun, 

 the conversion of matter into sugar occurs under the same 

 circumstances as the decomposition of carbonic acid. (141 and 

 279) 



232 Therefore, if fruit be produced in situations much ex- 

 posed to the sun, its sweetness will be augmented. 



233. And in proportion as it is deprived of the sun's direct 

 rays that quality will diminish. 



234. So that a fruit which when exposed to the sun is 

 sweet, when grown where no direct light will reach it will 

 be acid; as Pears, Cherries, &c. 



23-5- Hence acidity may be corrected by exposure to light ; 

 and excessive sweetness, or insipidity, by removal from light. 



236. It is the property of succulent fruits which are acid 

 when wild, to acquire sweetness when cultivated, losing a 

 part of their acid- 



237. -This probably arises from the augmentation of the 

 cellular tissue, which possibly has a greater power than 

 woody or vascular tissue of assisting in the formation of sugar. 



238. As a certain quantity of acid is essential to render fruit 

 agreeable to the palate, and as it is the property of cultivated 

 fruits to add to their saccharine matter, but not to form more 

 acid than when wild; it follows, that in selecting wild fruits for 

 domestication, those which are acid should be preferred, and 

 those which are sw r eet or insipid rejected. 



239. Unless recourse is had to hybridism ; when a wild 



