144 THE SURVIVAL OF THE UNLIKE. [v. 



that, on the contrary, the seeds of new varieties give 

 wide variations, which are usually in the direction of 

 improvement. It seems that this particular doctrine — 

 to which we shall now restrict the name "Van Mons' 

 theory," — was not originally deduced from observation, 

 but was a precognition. " The system of Van Mons upon 

 the means of producing the best fruits for the table 

 is not founded upon experience or practice," writes 

 Loiseleur-Deslongchamps ; "it is a preconceived idea 

 of the earlier years of the author, which he has endeav- 

 ored by every means to verify and develop, and which 

 he made the fond child of his imagination." Yet there 

 was some apparent basis for the generalization. Many 

 of the old varieties of fruits seemed to be failing, whilst 

 the new varieties were strong, healthy and productive. 

 There seems at times to be a tendency for old varieties 

 to deteriorate towards some assumed primitive or infe- 

 rior type. In fact, we hear everywhere at the present 

 day that varieties wear out with age, and we are cited to 

 the disappearance of once cherished forms for proof of 

 the statement. But we are learning to analyze these 

 instances of wearing out, and we seem to find, in every 

 instance, that there is some specific reason for the disap- 

 pearance of given varieties, and that their loss is not the 

 result of the operation of a general law. We now know 

 that the Bordeaux mixture is a specific for the so-called 

 running out of the Virgalieu pear, Catawba grape, and 

 other fungus -infested fruits ; that change in fashions 

 and demands has stranded varieties of intrinsic merits -, 

 that certain varieties have failed because they have been 

 taken into regions to which they were not adapted ; that 

 others have passed out because they are difficult to prop- 

 agate or are wayward growers, so that the nurserymen 



