LIFE AND OKGANISATION. 91 



distinction between them by metaphysical subtleties, we 

 may well admit that the questions they suggest are in great 

 measure the same in kind, and of like difficulty in solution. 

 The method of research we suggest through these common 

 relations, though often touched upon in part, has never been 

 systematically pursued. It would require varied experiments, 

 as well as minute observation. It must of necessity be an 

 assiduous labour, and divided among many ; but also a labour 

 of high interest, and aided by numberless facts already ascer- 

 tained, but not yet collated or reduced to order. A systematic 

 work on Instincts, derived from every province of animal 

 life, and carefully brought into relation with those various 

 degrees of reason which animals possess, would (even if but 

 partially completed) be of high value to physiological science 

 in its every part. 



Associated, though less closely, with the foregoing topics, 

 comes another enquiry which has earnestly engaged the 

 naturalists of our day; viz., the manner of distribution of 

 the types, genera, and species of animal life over the surface 

 of the globe. The diversities of such distribution have long 

 been noticed ; but to botanists, and especially to Decandolle, 

 we owe the first clear conception of geographical provinces, 

 within which are located certain predominant typical forms, 

 diffusing themselves as from a centre ; arrested in some cases 

 by the intervention of sea or land ; in other cases mingling 

 on the border with the types and characters of other pro- 

 vinces. In animal life also we find this local distribution, 

 with conterminous mingling and affinity of genera and 

 species, strongly marked; and though the boundaries of 

 such provinces are still not fully defined, we are sufficiently 

 assured of the fact to reason upon it as a part of the living 

 economy of the world. And a most curious fact it is; 

 depending, as it must do, either on the original conditions 

 of animal creation, or on the great revolutions of the earth's 



