462 TROPICAL NATURE 



shapes of the primary wing-feathers, in the relative length of 

 the hind toe, or in habits of life, as in roosting and building 

 on trees. But the above objection shows how completely 

 the principle of selection has been misunderstood. It is not 

 likely that characters selected by the caprice of man should 

 resemble differences preserved under natural conditions, either 

 from being of direct service to each species, or from standing 

 in correlation with other modified and serviceable structures. 

 Until man selects birds differing in the relative length of the 

 wing-feathers or toes, etc., no sensible change in these parts 

 should be expected. . . . With respect to the domestic races 

 not roosting or building in trees, it is obvious that fanciers 

 would never attend to or select such changes in habits." 



Studies of Cultivated and mid Plants 



Still more remarkable, perhaps, is the collection of facts 

 afforded by plants, which can be so much more easily culti- 

 vated and experimented upon than animals, while the general 

 phenomena they present are strikingly accordant in the two 

 kingdoms. As an example of the great mass of facts afforded 

 by horticulture, he records that three hundred distinct varie- 

 ties were produced, in the course of fifty years, from a single 

 wild rose (Eosa spinosissima). We find in these volumes 

 enormous collections of facts on bud- variation, or the occur- 

 rence of changes in the flower or leaf -buds of full-grown 

 plants, from which new varieties can be and often are pro- 

 duced; and, after a most full and interesting discussion of 

 the cases, it is shown that some are probably due to reversion 

 to an ancestral form, others to reversion to one parent when 

 the plant has been derived from a cross, and others, again, to 

 that spontaneous variability which seems to be the universal 

 characteristic of all living organisms. 



Three very interesting chapters are then devoted to the 

 subject of inheritance, and a host of strange and heretofore 

 inexplicable facts are brought together, compared, and classi- 

 fied, and shown to be in accordance with a few general prin- 

 ciples. Then follow five chapters on crossing and hybridism, 

 perhaps the most important in the whole work, since they 

 afford the clue to so much of the varied structure and com- 

 plex relations of animals and plants. Notwithstanding the 



