VI.] TWO CLASSES OF EVOLUTIONISTS. 165 



and applications should be tested, in a candid spirit, by 

 persons in every walk of life. Every enlightened person 

 is in some degree an evolutionist, and every occupation 

 is to some extent affected by the philosophy. 



It is not my purpose at this time to enter into any 

 discussion of the theories of evolution, but rather to 

 specify some of the bolder directions in which they are 

 capable of explaining or modifying the practices of the 

 farmer, more particularly of the horticulturist. Leaving 

 aside the specific inter-relations of evolution and hor- 

 ticulture, and ignoring the technicalities, let us take a 

 broad sweep of the subject, and endeavor to discover 

 those chief fundamental elements upon which the inquir- 

 ing mind can permanently rest. I shall need to say 

 something at the outset, however, of the shape in which 

 these theories have formulated themselves in the minds 

 of naturalists. That there is an evolution or progression 

 of forms, one giving rise to another, is an assumption no 

 longer doubted by biologists, and I shall, therefore, pre- 

 sent no arguments in support of the general hypothesis. 

 In the words of Haeckel, " The whole literature of mod- 

 ern biology, the whole of our present zoology and bot- 

 any, morphology and physiology, anthropology and psy- 

 chology, are pervaded and fertilized by the theory of 

 descent." The difficulties in the hypothesis all turn 

 upon the means or agencies which may be conceived to 

 have brought about this evolution. For our purpose we 

 may divide the philosophers of organic evolution into 

 two classes, — those who believe that the environment, or 

 conditions in which animals and plants live, directly 

 modify the organisms from generation to generation ; 

 and those who conceive that immediate effects of envi- 

 ronment have no permanent effect upon the species, but 



