UNITY OF DESIGN. 637 



that the original continuity of the series is indi- 

 cated by a few species presenting, in some res- 

 pects, intermediate characters, such as the Orni- 

 thorhyncus, between birds and mammalia, and 

 the Cetacea, between fishes and warm blooded 

 quadrupeds : for these are but detached links of 

 a broken chain, tending, indeed, to prove the 

 unity of the designs of Nature, but showing also 

 the specific character of each of her creative 

 efforts. The pursuit of remote and often fanciful 

 analogies has, by many of the continental physi- 

 ologists, been carried to an unwarrantable and 

 extravagant length : for the scope which is given 

 to the imagination in these seductive specu- 

 lations, by leading us far away from the path of 

 philosophical induction, tends rather to obstruct 

 than to advance the progress of real knowledge. 

 By confining our inquiries to more legitimate 

 objects, we shall avoid the delusion into which 

 one of the disciples of this transcendental school 

 appears to have fallen, when he announces, with 

 exultation, that the simple laws he has discovered 

 have now explained the universe ;* nor shall we 

 be disposed to lend a patient ear to the more 

 presumptuous reveries of another system-builder, 

 who, by assuming that there exists in organized 

 matter an inherent tendency to perfectibility, 



* "L'univers est explique, et nous le voyons ; c'est un petit 

 nombre de principes generaux et feconds qui nous en ont donne 

 la clef." Series, Ann. des Sc. Nat. xi. 50. 



