THE MULES. 337 



its modifications, may with propriety refrain from 

 denying the probability of those other flexibihties in 

 the laws of propagation which we have here advo- 

 cated, although the evidence as yet remains in some 

 cases presumptive, and we only descry the workings 

 of Almighty Beneficence darkly. 



With the limited knowledge we as yet possess, 

 we are not justified assuming as law, without strik- 

 ing exceptions, that sterility is a necessary result of 

 the commixture of different species, and fertile off- 

 spring an unerring proof of their identity. Frederick 

 Cuvier, notwithstanding an evident disinclination to 

 depart in opinion from the conclusions of the great 

 and eloquent Buffon, is obliged to qualify his assent, 

 and points out himself the disregard of his own con- 

 clusions and the unsatisfactory state of opinion that 

 noble writer and his followers are driven to when 

 they attempt rigorously to uphold them. 



" In this science (zoology), as in all those depend- 

 ing upon observation, the generalisation of facts," 

 says F. Cuvier, * " is the surest guide to truth ; but 

 the inductions to be drawn, in order to escape false 

 conclusions, must rest upon facts strictly amenable to 

 comparison. Nothing appears more natural, from 

 an observation of the phenomena of the succession of 

 individuals in an ascending or a descending line 

 being similar to each other, than that they are of 

 the same species; and this consideration, coupled 



* Frederick Cuvier's great work, Lithographed Mammals of 

 the Menagerie of Paris. Folio, coloured. Articles Zebra and 

 Mule. 



