Moritz Wagner has lately published an interesting essay on this subject, and has shown that the service rendered by isolation in preventing crosses between newly-formed varieties is probably greater even than I supposed.
Moritz Wagner-ek gai honi buruz saiakera interesgarri bat argitaratu du oraintsu, eta isolamenduak aldaki formaberrien arteko gurutzaketa ekiditeko egiten duen zerbitzua nik neuk uste nuena baino ere handiagoa bide dela frogatu du.