10 EXPERIMENTAL EVOLUTION 



nated in nature's garden and not in man's^ has been left over to 

 us from the last generation — it is the inheritance of an acquired 

 character. John Ray, towards the close of the seventeenth cen- 

 tury, appears to have been the first to use the word species in its 

 technical natural history sense, and the matter of origin was an 

 important factor in his conception of what a species is. Linnaeus' 

 phrase is familiar: "We reckon as many species as there were 

 forms created in the beginning." Darwin elaborated the new con- 

 ception — that a species is simply a congregation of individuals 

 which are more like each other than they are like any other con- 

 gregation — and with a freedom from prejudice which is rarely 

 attained even by his most devoted adherents, he declared that 

 " one new variety raised by man will be a more important and 

 interesting subject for study than one more species added to the 

 infinitude of already recorded species. The old naturalists threw 

 the origin of the species back beyond known causes ; Darwin 

 endeavoured to discover the "Origin of Species," and it is signifi- 

 cant that he set out without giving any definition of what a species 

 is. I have said this much for the purpose of showing that it is 

 important, when we demand that a new species be created as a 

 proof of evolution, that we are ourselves open to the conviction 

 that the thing can be done. 



I have said that no modern naturalist would define a species 

 in such terms that some horticultural types could be excluded, 

 even if he desired that they should be omitted. Haeckel's excel- 

 lent definition admits many of them. In his view, the word 

 species " serves as the common designation of all individual 

 animals or plants, which are equal in all essential matters of form, 

 and are only distinguished by quite subordinate characters." It is 

 impossible, however, to actually determine, if one has a species 

 in hand, by applying a definition. One must show that his new 

 type — if it is a plant — has botanical characters as well marked as 

 similar accepted species have ; and these characters must show, 

 as a whole, a general tendency towards permanency when the 

 plant is normally propagated by seeds. He must measure his 

 type by the rule of accepted botanical practice. If the same plant 

 were found wild, so that all prejudice might be removed, would 

 the botanist unhesitatingly describe it as a new species ? If yes, 



