400 CONCLUSION [CHAP. XV. 



form be a true species. This, I feel sure and I speak after ex- 

 perience, will be no slight relief. The endless disputes whether 

 or not some fifty species of British brambles are good species will 

 cease. Systematists will have only to decide (not that this will be 

 easy) whether any form be sufficiently constant and distinct from 

 other forms, to be capable of definition ; and if definable, whether 

 the differences be sufficiently important to deserve a specific name. 

 This latter point will become a far more essential consideration 

 than it is at present ; for differences, however slight, between any 

 two forms, if not blended by intermediate gradations, are looked 

 at by most naturalists as sufficient to raise both forms to the rank 

 of species. 



Hereafter we shall be compelled to acknowledge that the only 

 distinction between species and well-marked varieties is, that the 

 latter are known, or believed, to be connected at the present day 

 by intermediate gradations whereas species were formerly thus con- 

 nected. Hence, without rejecting the consideration of the present 

 existence of intermediate gradations between any two forms, we 

 shall be led to weigh more carefully and to value higher the 

 actual amount of difference between them. It is quite possible 

 that forms now generally acknowledged to be merely varieties 

 may hereafter be thought worthy of specific names ; and in this 

 case scientific and common language, will come into accordance. 

 In short, we shall have to treat species in the same manner as 

 those naturalists treat genera, who admit that genera are merely 

 artificial combinations made for convenience. This may not be a 

 cheering prospect ; but we shall at least be freed from the vain 

 search for the undiscovered and undiscoverable essence of the term 

 species. 



The other and more general departments of natural history will 

 rise greatly in interest. The terms used by naturalists, of affinity, 

 relationship, community of type, paternity, morphology, adaptive 

 characters, rudimentary and aborted organs, &c., will cease to be 

 metaphorical, and will have a plain signification. When we no 

 longer look at an organic being as a savage looks at a ship, as 

 something wholly beyond his comprehension; when we regard 

 every production of nature as one which has had a long history; 

 when we contemplate every complex structure and instinct as the 

 summing up of many contrivances, each useful to the possessor, 

 in the same way as any great mechanical invention is the summing 

 up of the labour, the experience, the reason, and even the blunders 

 of numerous workmen; when we thus view each organic being, 

 how far more interesting I speak from experiencedoes the 

 study of natural history become ! 



A grand and almost untrodden field of inquiry will be opened, 

 on the causes and laws of variation, on correlation, on the effects 



