164 Natural Theology 



of beauty in the flower by doubling, and the increase 

 of the fruit in size, beauty, and flavor, are of no ad- 

 vantage to the fruit itself, nor to the species ; but 

 in some cases they are a draft upon the plant for no 

 purpose in its own economy. 



5. Those plants that by variation lose the power 

 of producing seed, can always be propagated in 

 other ways, as by slips or bulbs. Nature, as though 

 careful for the preservation of the species, never 

 allows any plant, by its own law of growth, to lose 

 the power of producing seed, unless she has given 

 to it means other than the seed, for the perpetuation 

 of its kind. 



6. Variation is most common and rapid in those 

 plants which are most useful to man for cultivation, 

 and which must go with him over most of the earth. 

 It may be said that they are most useful because 

 they happen to vary ; but their readiness to vary, 

 certainly was not the cause of their first cultivation. 

 They were selected for some particular good, as for 

 fruit, or for beauty of flower, or leaf, or some other 

 desirable property. The characteristic for which 

 each one was first selected, is the leading idea of the 

 plant ; and in that direction all its variations under 

 cultivation have tended. The rose, in all its vari- 

 eties, is to-day cultivated for the same reason for 

 which it was first cultivated, for its beauty ; the 

 apple-tree for its fruit, the sugar-cane for its sweet- 

 ness, and so on, through the list of cultivated plants. 

 We might multiply propositions and examples, if our 

 space allowed. As they would not differ in kind, 



