18 On the Production of Hybrid Vegetables. 



separated. On the other hand, Mr. Knight has failed, as 

 yet, of producing a fertile plant between the American and 

 European Strawberries : but are we to conclude from that 

 circumstance, that plants, so nearly allied as the Scarlet and 

 Alpine Strawberries, were from the creation of the world dis- 

 tinct, and at the same time hold that all the African Gladioli, 

 between which (permanently dissimilar as they are in ap- 

 pearance) I can raise fertile intermixtures, were originally 

 one species ? Such an opinion would be so paradoxical, that 

 it would require to be supported by very clear proof; and 

 yet it would be difficult, by experiments, in any manner to 

 confirm it. 



It is not even true that all mules amongst animals are 

 entirely sterile. There are well attested instances of the 

 fertility of the mule between the ass and the mare ; and mules 

 between the gold-finch and canary-bird, the distinction of 

 which no naturalist could deny, are frequently known to 

 breed ; and I understand that all the more beautiful mules 

 are produced by a second cross with the canary-bird. I 

 have known the mule siskin couple with a canary-bird ; and 

 I understand that the mules between two very distinct birds, 

 the common pheasant and the silver pheasant, have proved 

 fertile. The analogy, therefore, of animals, if such could be 

 relied on, in considering the generation of vegetables, would 

 not completely establish fertility as the test of a common 

 origin. The organs in mule animals are said to be perfect, 

 and the cause of their rarely breeding is not ascertained, 

 though it is perhaps a sluggishness of constitution, as the 

 equine mule is said to be more fertile in warmer countries. 

 I suspect also, that the plants which thrive in a high tempe- 



