64 REVIEWS. 



exerts a specific action, which not only favors and quickens 

 the operation of the pollen of its own sj)ecies, but resists and 

 retards the action of that of another ; so that the artist has 

 not only to forestall the natural operation, but to experience 

 opposition to his conducting the artificial one. 



" 2. Even when the impregnation is once effected, very few 

 seeds are produced ; still fewer of these ripen ; and fewest of 

 all become healthy plants, capable of maintaining an inde- 

 j)endent existence. 



" 3. The offspring of a hybrid has never yet been known 

 to possess a character foreign to those of its parents ; but it 

 blends those of each; — whence hybridization must be re- 

 garded as a means of obliterating, not creating, species. 



" 4. The offspring of hybrids are almost invariably abso- 

 lutely barren, nor do we know an authenticated instance of 

 the second generation maturing its seeds. 



" 5. In the animal kingdom hybrids are still rarer in an 

 artificial state, are all but unknown in a natural one, and are 

 almost invariably barren." 



Perhaps some of these dicta are too unqualifiedly stated ; 

 indeed they are manifestly intended to affirm the results to 

 which the whole evidence points, rather than those which can 

 be said to be thoroughly verified. 



The third proposition, however, is absolutely true ; and, in 

 connection with it, well do our authors say, that all we could 

 legitimately conclude is, that were hybrids of the general 

 occurrence which some botanists imagine, they would long ago 

 have obliterated all traces of species as definite creations ; 

 whereas, exceptional in art, and not proven if not almost im- 

 possible in nature, they cannot be assumed to have produced 

 any appreciable result. There is one point, however, which 

 our authors do not take into consideration, but which should 

 not be overlooked, namely, what is generally admitted as a 

 fact, that a hybrid may readily be fertilized by the pollen of 

 either of its parents ; and that if hj^brid plants are occasion- 

 ally produced in nature, they would ordinarily stand a very 

 good chance of being fertilized in this way. In such cases 

 they are said to revert to the type of the species of the im- 



