Apparent Exceptions. 165 



they arc not needed for the argument. Apparent 

 eptions to the propositions already stated may 

 undoubtedly be pointed out, for it is well understood 

 by naturalists that nature does nothing per saltuin. 

 Hardly a group of plants can be examined in which 

 there will not be found one or more that the fami- 

 ly description will not embrace, in all particulars. 

 There are also some plants so valuable for several 

 purposes, that it would be difficult to determine, in 

 every case, the leading idea. They are made for a 

 double purpose, and may develop in either direction. 

 The apple-tree, with double blossoms, or the tomato, 

 with tubers upon it, would not, therefore, with any 

 candid person, affect the bearing of the propositions. 

 If a law of natu: ly discovered, all exceptions 



are either merely apparent, or if real, are found to 

 be special provisions for some wise purpose. It is 

 the general law of variation that we now wish to 

 present for consideration, in the propositions just 

 enunciated. If these propositions have any signifi- 

 cance, to what do they tend ? Certainly to show 

 that the vegetable kingdom is not an end to itself. 

 Men and animals do not make use of plants because 

 they happen to be what they are ; but the plants 

 are constituted as they are, for the sake of the ani- 

 mal kingdom, and many of them with a direct refer- 

 ence to man as an intellectual and moral being. It 

 is by the law of variation of species that they are 

 most perfectly fitted for these high purposes. 



In almost every department of plant life, the 

 changes can be referred primarily to the good of the 



