62 BOARD OF AGRICULTURE. 



the original stock, but only in certain directions. On this point 

 we quote the language of a distinguished scientific man who has 

 lately written much upon this subject. It would be difficult to 

 find, in the writings of any other author, all that we really know 

 on this subject, condensed into so few words : — 



" The former [variation"] has never yet been shown to have its cause 

 in ' external influences/ nor to occur at random. As we have elsewhere 

 insisted, if not inexplicable, it has never been explained ; all that we 

 can yet say is, that plants and animals are prone to vary, and that some 

 conditions favor variations." * 



We thus confess our ignorance of the natural causes that 

 produce variation. "We propose to discuss its final cause. This 

 implies that there is in it a purpose. If there is in the variation 

 of objects in nature a purpose, that purpose must have relation 

 to the objects themselves, or to some other beings connected 

 with them or in some way related to them. Our special object 

 will be to show that all variation from original forms in the 

 animal and vegetable kingdoms is not in general for the good of 

 the object in which it occurs, but for the good of other objects 

 in some way related to it. We think it will readily appear to 

 any careful observer, that much of the variation in both of these 

 kingdoms has special reference to man as an intellectual and 

 moral being. But we shall, for want of time, confine our 

 present examination mainly to plants. 



For what purpose are the petals of the flower, the crown of 

 beauty to the plant ? Certainly they are not absolutely essential 

 in the production of seed, for many plants are without them. 

 And if in any case they are deemed, essential, certainly the beau- 

 tiful pattern of the petal, its numberless modifications and 

 delicate tints, adjusted with masterly accuracy, arc not necessary 

 parts in the economy of plants. Of what use to the plant is 

 that row of sterile flowers that adorns so many of our composite, 

 the Rudbcckias and helianths, or that curious circle of sterile 

 flowers bordering the cymes of hydrangeas and some of our 

 viburnums? "We may be told that they have no use, or that 

 these apparently useless parts will at some time be found to be 

 of importance in the economy of the plant, aiding directly or 

 indirectly in the perpetuation of the species. 



* Professor Asa Gray. 



