False Atavism 199 



that it cannot reasonably be subjected to any 

 doubt. It must be conceded to be a fact, that 

 varieties as a rule revert to their species under 

 the ordinary circumstances of commercial cul- 

 ture. And I cannot see any reason why this 

 fact should not be considered as stating a prin- 

 cipal difference between varieties and species, 

 since true species never sport into one another. 



My objection only refers to the explanation 

 of the observed facts. According to my view 

 nearly all these ordinary reversions are due to 

 crosses, and it is for this reason that I proposed 

 to call them by a separate name, that of ' ' vicin- 

 ists." Varieties then, by means of such spon- 

 taneous intercrossing sport into one another, 

 while species either do not cross, or when cross- 

 ing produce hybrids that are otherwise consti- 

 tuted and do not give the impression of atavis- 

 tic reversion. 



I must not be content with proposing this 

 new conception, but must give the facts on 

 which this assumption rests. These facts are 

 the results of simple experiments, which never- 

 theless are by no means easy to carry out, as 

 they require the utmost care to secure the 

 absolute purity of the seeds that are employed. 

 This can only be guaranteed by previous cul- 

 tures of isolated plants or groups of plants, or 

 by artificial pollination. 



