SERIES OF NATURE. 61 



caused either by the annihilation of some original group or 

 species, in consequence of some great convulsion of nature, 

 or that the objects required to fill it up are still in existence, 

 but have not yet been discovered; and this opinion is founded 

 upon a dictum of Linnseus's, ' Natura saltus non facit.' If 

 this dictum be literally interpreted, according to the evident 

 meaning of the word saltus, few will be disposed to object to 

 it, since both observation and analogy combine to prove 

 that there must be a regular approximation of things to each 

 other in the works of God; and that, could we see the whole 

 according to His original plan, we should find no violent 

 interval to break up that approximation : but if it be con- 

 tended that in this plan there is no difference in the juxta- 

 position of the lowest groups or individuals, and never any 

 interval between them, I think we are going further than 

 either observation or analogy will warrant. Were this really 

 and strictly the case, it seems to follow that every group or 

 individual species must, on one side, borrow half its charac- 

 ters from the preceding group or species ; and on the other, 

 impart half to the succeeding. (Query, whether every real 

 species or group has not some one or more peculiar charac- 

 ters, which it neither derives from its predecessor nor imparts 

 to its successor in a series ?) But one of the most evident 

 laws of creation is variety, and if we survey all the works of 

 the MOST HIGH, we shall nowhere discover that kind of 

 order and symmetry that this strict interpretation implies. 

 The general march of nature, therefore, seems to say, that 

 there must be varying though not violent intervals in the 

 series of beings, or, in other words, some conterminous spe- 

 cies or groups have more characters in common than others." 

 Very few words will suffice upon the nature of species, a 

 term employed to designate those groups of animals which 

 (save as respects sexual distinctions) possess a perfect con- 

 formity in their characters, which indeed they have unin- 



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