4 THE DARWINIAN HYPOTHESIS i 



distinct species than when fertilised by its proper 

 pollen ! On the other hand, the famous Gaertner, 

 though he took the greatest pains to cross the 

 Primrose and the Cowslip, succeeded only once or 

 twice in several years ; and yet it is a well- 

 established fact that the Primrose and the Cow- 

 slip are only varieties of the same kind of plant. 

 Again, such cases as the following are well estab- 

 lished. The female of species A, if crossed with 

 the male of species B, is fertile ; but, if the female 

 of B is crossed with the male of A, she remains 

 barren. Facts of this kind destroy the value of 

 the supposed criterion. 



If, weary of the endless difficulties involved in 

 the determination of species, the investigator, 

 contenting himself with the rough practical 

 distinction of separable kinds, endeavours to 

 study them as they occur in nature to ascertain 

 their relations to the conditions which surround 

 them, their mutual harmonies and discordancies of 

 structure, the bond of union of their present and 

 their past history, he finds himself, according to 

 the received notions, in a mighty maze, and with, 

 at most, the dimmest adumbration of a plan. 

 If he starts with any one clear conviction, it is 

 that every part of a living creature is cunningly 

 adapted to some special use in its life. Has not 

 his Paley told him that that seemingly useless 

 organ, the spleen, is beautifully adjusted as so 

 much packing between the other organs? And 



