PLAN AND PURPOSE IN NATURE. 223 



SO vast is the distinction between dead matter and living, T feel 

 that we are justified in inferring, not only the ordinary guidance, 

 but also the frequent extra-ordinary interposition, of Omnipotent 

 Power from the creation of the first living cell to that of man 

 himself. The difference between inert inorganic matter and a 

 living organism is as vast as space itself. 



There are several other points in the author's essay which I 

 would like to refer to, but I shall confine myself to one or two. 

 The author has referred to Lord Kelvin's theory stated in his 

 address to this Institute, to account for the quantity of oxygen 

 necessary for the support of the future animal life. The view 

 which appears to me the more probable one is that I have stated 

 in my paper on the question, " How the waters of the ocean 

 became salt" {Trans. Vic. Inst.., vol. xxvii), in which I inferred that 

 the primeval atmosphere was largely composed of carbon-dioside 

 (carbonic acid gas), and that the elimination of the carbon by the 

 agency of plants, notably in the Carboniferous period, would have 

 left free large quantities of oxygen for the future air-breathing 

 inhabitants of the globe. 



There is only one other note I wish to make to Sec. 19, where 

 Dr. Kidd I'efers to the efiect of the incoming cold of the glacial 

 epoch in killing off many forms unsuited to withstand its severity, 

 and the creation of new forms more fitted for the environment. 

 Undoubtedly many animals were locally killed off in the northern 

 hemisphere by the severity of the glacial climate, but com- 

 paratively few were actually exterminated, and no new forms, as 

 far as we know, were subsequently introduced with the possible 

 exception of man himself. There was, however, a general 

 migration of animals to more southerly and warmer climes — for 

 example, from Europe and Asia into Africa, as shown by 

 Dr. Alfred Wallace. 



Eev. F. A. Walker, D.D., F.L.S. — There are two or three points 

 upon which I should be glad to have the opinion of the author of 

 this learned paper. 



Butterflies and other insects are ranked, in section 17, as occur- 

 ring at remote epochs. 



It would be very interesting to learn if butterflies are preserved 

 in strata, because I have been told that such specimens are very 

 few and far between, naturally in consequence of their fragility 

 and the impossibility of their beautiful delicate hues being 

 preserved throughout the ages. There are two instances men- 

 tioned in Mr. Butler's book. 



R 2 



