FRUITS, VEGETABLES, AND FLOWERS. 13 



larger and better in flavour, and frequently earlier, than that on 

 the lower and shadier branches ; and by taking due and intel- 

 ligent advantage of this fact, we might possibly obtain earlier 

 and later varieties of some of our finest and best -flavoured 

 fruits. 



The explanation of the unequal effect of the same degree 

 of temperature is, according to M. de Candolle, owing to the 

 buds of a tree being engaged in a perpetual struggle. Badly 

 placed or imperfectly developed buds develop imperfect shoots. 

 The earliest shoots have the advantage so long as they are not 

 injured by frost. In this way a selective process and an adap- 

 tation of the tree to the climate are carried on. This is the 

 more probable from the individuality possessed by the buds, 

 and of which we avail ourselves in the operation of grafting. 

 Thus M. de Candolle cites a case of a Horse-chestnut, near 

 Geneva, which produces year by year, on a certain branch, 

 double flowers. From this branch grafts have been taken 

 which have furnished all the double Horse-chestnuts in Europe. 

 Hence it may be concluded that certain branches may also be 

 (as we know to be the case) earlier or later in development 

 than others on the same tree, and that buds taken from 

 these branches will preserve their characteristics when grafted. 

 In the north precocity is sometimes advantageous, sometimes 

 not so. In the south precocity seems generally beneficial, and 

 yet it is in the south that species require the most heat to 

 develop themselves. The principal cause of the difference in 

 the vegetation of the north and of the south appears to be con- 

 nected with the winter rest of plants. After a season of great 

 external activity the plant loses its leaves and ceases to grow ; 

 but in the interior of the plant great changes and modifications 

 of material are taking place at this time, in anticipation of the 

 development of the buds at a subsequent date. In the north 

 the internal activity of the plant is specially marked. This is 

 one reason why heat acts more rapidly in the north than in the 

 south. On the other hand, in southern countries, the plant 

 continues to grow superficially, and a larger proportion of sap 

 being utilised at the surface, there is not so much available 

 for the buds in spring. The mechanical effects of the same 

 amount of heat should be everywhere the same, but when it is 

 exerted on different materials to transport or modify them, it is 

 clear that the effect will be different. Such, in brief, is M. de 

 Candolle's explanation of a phenomenon of which he has, by 

 his experiments, given additional confirmation. 



Careful study of nature will teach us much in the way of 

 altering existing forms of vegetation. For example, climbing 



