THE VEGETABLE WORLD. 291 



influences which have called forth an aberration from the 

 original form of the plant continue to act in the same way, 

 not for centuries or tens of centuries, but for ten or a 

 hundred thousand years; will not, at last, as the variety 

 thus becomes a sub-species, so also this become so perma- 

 nent, that we shall and must describe it as a species. 

 Then, if the first cell be given, the foregoing points out 

 how the whole wealth of the vegetable kingdom may have 

 been formed by a gradual passage from it through 

 varieties, sub-species and species, and thus onward, 

 beginning anew from each species in a space of time, in- 

 deed, of which we have no conception, for which, however, 

 since there is nothing real wanting, we may provide at 

 pleasure in our dreams ; for it may be mentioned here that 

 all the recent distinguished Geologists come ever more and 

 more to the opinion, that very much, in the formation of 

 the crust of our earth, which was formerly ascribed to 

 violent, convulsive and sudden revolutions, has rather been 

 the product of forces acting slowly through the course of 

 enormous periods of time. The Falls of Niagara, for 



these latter exclusively, or at all events especially, occur in an 

 abundance of sportive forms, whereby they deviate more or less from 

 the primary character of their species. I name as examples, such 

 species as, Thalictrum minus, Ranunclus arvensis, Viola tricolor, 

 Silene gattica and inflata, Spergula arvensis, Medicago falcata, 

 iupulina, tribuloides, Vicia villosa, sepium, grandiflora, angustifolia, 

 Knautia hybrida, arvensis, Scabiosa gramuntia, Cirsium arvense, 

 Taraxacum officinale, Galeopsis ladanum, Agrostis stolonifera, vulgaris, 

 Aira ctfspitosa, Festuca ovina, rubra, Bromus secalinus. Nay, many 

 species may have originated from such variations, even within his- 

 torical time, as Thalictrum minus and majus, Veronica praecox and 

 triphyllos. But that all true cultivated plants occur in countless 

 varieties it is scarcely necessary to mention, since Peas, Cabbage and 

 Potatoes, not to consider fruits, are each sufficient evidence of this 

 truth. 



19* 



