Note {80} — PART I.
Reading edition
The meaning of this sentence is made clear by a passage in the MS. of 1844:—“Until man selects two varieties from the same stock, adapted to two climates or to other different external conditions, and confines each rigidly for one or several thousand years to such conditions, always selecting the individuals best adapted to them, he cannot be said to have even commenced the experiment.” That is, the attempt to produce mutually sterile domestic breeds.