OLA SSI FTC A TION. 4 1 5 



arisen within historical times, and varieties approaching 

 to sub-species may often be produced by the horticul- 

 turist in a few years. Such varieties can easily be brought 

 back to their original form, or, if placed in the original 

 circumstances, will themselves revert to that form ; but 

 according to Darwin's views all forms are capable of un- 

 limited change, and, it might possibly be, unlimited re- 

 version, if sufficient time and suitable circumstances be 

 granted. 



Many fruitless and erroneous attempts have been made 

 to establish some rigorous criterion of specific and generic 

 difference, so that these classes might have a definite value 

 or rank in all branches of biology. Linnaeus adopted the 

 view that the species was to be defined as a distinct 

 Creation saying n , ' Species tot numeramus, quot diversse 

 format in principio sunt creatae,' or again, * Species tot sunt, 

 quot diversas formas ab initio produxit Infmitum Ens ; 

 quae formae, secundum generationis inditas leges, pro- 

 duxere plures, at sibi semper similes/ Of genera he also 

 says , ' Genus omne est naturale, in primordio tale crea- 

 tum/ It was a common doctrine added to and essential 

 to that of distinct creation that these species could not 

 produce intermediate and variable forms, so that we find 

 Linnaeus in another work obliged by the ascertained exis- 

 tence of hybrids to take a different view; he says^, 'Novas 

 species immo et genera ex copula diversarum specierum 

 in regno vegetabilium oriri primo intuitu paradoxum 

 videtur ; interim observationes sic fieri non ita dissuadent/ 

 Even supposing in the present day that we could assent 

 to the notion of a certain number of distinct creational 

 acts, this notion would not help us in the theory of classi- 



n ' Pliilosophia Botanica ' (1770), 157, p. 99. 

 Ibid, 159, p. 100. 



P ' Amoenitates Academicee ' (1744), vol. i. p. 70. Quoted in 'Edin- 

 burgh Review,' October 1868, vol. cxxviii. pp. 416, 417. 



