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JOURNAL OF THE ROYAL HORTICULTURAL SOCIETY. 



keep at all in line with modem botanical literature, but these few 

 authorities are amply sufficient to show that those who deny to plants 

 the possibility of species changing in type when gradually exposed to 

 utterly different conditions of life have a fairly difficult task before 

 them. 



But if one accepts the view that all these climatic factors, sunshine, 

 moisture, wind and root water do act upon the delicate, complex struc- 

 ture of vegetable protoplasm and produce responses as inevitably as a 

 new sugar will affect a yeast colony accustomed to some other medium, 

 then it seems to me that the origin of species can be up to a certain 

 point understood. 



If one wishes to induce variation artificially, it would seem best to 

 select the very best seed likely to produce the strongest and most 

 vigorous seedlings. Then it might be worth while to treat these seed- 

 lings as badly as possible, exposing them to all sorts of hardships with- 

 out quite killing them. Such treatment will in all probability induce 

 some sort of change, which may manifest itself more clearly when the 

 plants are suddenly changed into thoroughly congenial conditions. 



All evil influences, whether poisons or injuries by wounds and 

 mutilations, seem, if not too severe, to promote a greatly enhanced 

 respiration. 



Perhaps this increased respiration may upset the regular habit of the 

 species, but the particular treatment entirely depends upon what special 

 result is required. 



