GEOGRAPHICAL DISTRIBUTION OF PLANTS. 287 



the hypothesis of a spread of terrestrial vegetation from 

 the sea into the lands adjacent. The community of forms 

 in the various regions opposed to each other merely indi- 

 cates a distinct marine creation in each of the oceanic 

 areas respectively interposed, and which would naturally 

 advance into the lands nearest to it as far as circumstances 

 of soil and climate were found agreeable.* 



There is still the difficulty of accounting for the orig- 

 ination of the first forms of life in the various lines after- 

 wards pursued to a high development. How was the in- 

 organic converted into the first rudiments of the organic ? 

 Whence, and of what nature was the impulse that first 

 kindled sensation and intelligence upon this sphere? A 

 suggestion on these subjects is hazarded in my book ; but 

 though we were to consider the matter as an entire mys- 

 tery, it is, after all, only so in the same degree, and to the 

 same effect, as the commencement of a new being from a 

 little germ is a mystery to us, although we know that it is 

 one of the most familiar of all natural events. This last 

 marvel we know to be under natural law, though we can- 

 not otherwise explain it. If we can regard the origin and 

 development of life upon our planet as having been 

 equally under natural law, the whole point is gained ; for 

 we are not so much inquiring in order to say how ? as 

 was it within or beyond the natural ? We have seen, 

 then, as I conceive, that all the associated truths of 

 science go to this point. The whole concur to say, that 

 to believe an exception in this particular of the history 

 of nature, is an absurdity. Difficulties there may be in 

 treating the case positively ; some facts of inferior impor- 

 tance may seem to point to an opposite conclusion ; but 

 i*n the balance of the two sets of evidences, those for a 

 universality of natural law down-weigh the other beyond 

 calculation. 



I have now to allude to a class of objections different 

 from those made on scientific grounds, but fortunately not 



* It is, perhaps, hardly necessary here to advert to any explana- 

 tion which might be brought from the diffusion of seeds by ocean 

 currents, because the directness of the opposition of the fields of 

 these iloras to each other across the Channel is obviously incon- 

 sistent with that idea. In such a case, the constituents of the va- 

 rious floras would have been confused amongst each other by tht 

 diversity of currents in the intermediate seas. Mr. Forbes plainly 

 confesses this explanation to be inadmissible in the present case ; 

 and, of course, it is not the right explanation in any other. 



