IMPROVEMENT OF CULTIVATED PLANTS. Ill 



powerful. There is also the attraction or influence of the im- 

 mediate parent, less powerful than the aggregate of the ances- 

 try, but more close, which ever tends to impress upon the off- 

 spring all the parental peculiarities. So, when the parent has 

 no salient individual characteristics, both the longer and the 

 shorter lines of force are parallel, and combine to produce the 

 same result. But whenever the immediate parent deviates 

 from the type, its influence upon its offspring is no longer 

 parallel with that of the ancestry ; so the tendency of the off- 

 spring to vary no longer radiates around the type of the 

 species as a centre, but around some point upon the line which 

 represents the amount of its deviation from the type. Left 

 to themselves, as Mr. Vilmorin proceeds to remark, such varie- 

 ties mostly perish in the vast number of individuals which 

 annually disappear, — or else, we may add, are obliterated in 

 the next generation through cross-fertilization by pollen of the 

 surrounding individuals of the typical sort, — whence results 

 the general fixity of species in Nature. But under man's 

 protecting care they are preserved and multiplied, perhaps 

 still further modified, and the better sorts fixed by selection 

 and segregation. 



Keeping these principles in view, Mr. Vilmorin concluded 

 that, in order to obtain varieties of any particular sort, his 

 first endeavor should be to elicit variation in any direction 

 whatever ; that is, he selected his seed simply from those in- 

 dividuals which differed most from the type of the species, 

 however unlike the state it was desired to originate. Repeat- 

 ing this in the second, third, and the succeeding generations, 

 the resulting plants were found to have a tendency to vary 

 widely, as was anticipated ; being loosed, as it w^ere, from the 

 ancestral influence, which no longer acted upon a straight 

 and continuous line, but upon one broken and interrupted 

 by the opposing action of the immediate parents and grand- 

 parents. Thus confused by the contrariety of its inherited 

 tendencies, it is the more free to sport in various ways ; and 

 we have only to select those variations which manifest the 

 qualities desired, as the progenitors of the new race, and to 

 develop and fix the product by selection upon the same prin- 

 ciple continued for several generations. 



