118 JOURNAL OF THE ROYAL HORTICULTURAL SOCIETY. 



partake of this vigour, and consequently enable larger and larger types to 

 be acquired. This, however, is not natural selection at all, and the differ- 

 entiation thus induced is fundamentally different from those spontaneous 

 departures from the parental type, embracing "sports " or " mutations " 

 and all grades of subvariation such as Darwin undoubtedly had in view. 



Of course if Professor Henslow confines himself to highly cultivated 

 plants, he is naturally confirmed in his idea that variation is induced by 

 change of environment, and only occurs when that occurs, being always 

 sympathetically responsive thereto. When, however, he applies such a 

 deduction to the wild and constant varieties of which I treat, or even to 

 " sports " under culture, it becomes necessary to combat such a contention 

 and to indicate the fallacy upon which it is based. 



