the way in which they touch upon the De Vries Theory. 

 This has been omitted purposely, for while the results of 

 Mendel's original experiments in the breeding of peas 

 might be cited at length, I doubt if an apter or more 

 significant example could be found than the one which 

 Professor Wilson used, and as Professor Wilson himself 

 said, the explanation while not abstruse is one that requires 

 considerable preparatory consideration. The Mutation 

 Theory has been developed more in detail, as representing 

 a type of research. Being one of the latest and most im- 

 portant contributions to biological science, and being also 

 entirely germane to the subject in hand, it has seemed 

 proper to devote some time to its consideration. At many 

 points do the fields of modern botany and modern zo- 

 ology touch, but perhaps it is nowhere so evident as in 

 great problems like these. Here the two sciences work in 

 generous rivalry, each eager to add its contribution to the 

 store of general knowledge, to utilize such information as 

 the sister science brings, to criticize it if need be, but 

 always to accord it a respectful hearing 



So much then for the purely theoretical side of botani- 

 cal research of which I have presented a hasty glimpse. It 

 is necessary before closing to make some reference to the 

 utilitarian aspect; where and how botany directly serves 

 the material needs of man. I hold it myself to be a matter 

 of some pride that a science like botany with a side so 

 purely theoretical and impractical can also lend itself to 

 further, in such important ways as it does, the well-being 

 of mankind, for in the direct application of botanical in- 

 formation to agricultural questions the ways and means 

 of life may be ameliorated. Moreover, it is some of the 

 most theoretical and recondite researches which have led 

 to the most important practical results. 



It is possible to consider only a few phases of the prac- 

 tical application of botany, and I will choose those which 



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