276 NOTE CONCLUSORY. 



that others were grounded on false assumptions regarding the 

 theory itself. For instance, there is nothing in it to imply 

 that the early animals were imperfect or of rude form ; they 

 only are low in the scale. Neither does the development 

 theory forbid that the early lacertine sauria should have had 

 better teeth than the same family in our own time ; the 

 explanation is, that the transitions from class to class were, 

 in general, comparatively great advances in development, and 

 comparatively independent of physical conditions, while some 

 of the inferior mutations were, partly through the agency of 

 physical conditions, towards a reduction in some of the ex- 

 ternal features of organization, particularly in the teeth and 

 the character of the locomotive system ; nature being, as was 

 said from the first in this work, alike willing to go forward 

 and to go back, at least within a certain range. Partly by 

 this general width of class transitions, were the so-called breaks 

 to be accounted for for example, that which seems to isolate 

 the birds. Partly, these breaks were owing to blanks in the 

 series of deposits, as suggested by some of the geologists 

 themselves. It therefore seemed sufficient, with regard to 

 this class of objections, to present the statements to which 

 they refer in such a manner and with such explanations as 

 might quietly set them aside. This I have likewise done. 



The rest of the opposition was solely based in preconceptions 

 of a different nature with regard to the history of the world. 

 Here the only question, of course, was as to the comparative 

 strength of the grounds for these preconceptions. Did they 

 rest on positive natural evidence ? were they more in harmony 

 with what is ascertained in science than my views ? It was 

 always assumed that these preconceptions were of good founda- 

 tion of one kind or another ; but the assumption could bear 

 no examination. View for a moment the objection from scrip- 

 ture : the same would hold equally well against the heliocen- 

 tric theory of the solar system, or the now undoubted fact that 

 the earth passed through mutations extending to many thou- 

 sand years, before the existence of man ! As to the geologists' 

 notion of successive creations by special fiat, it is but a notion 

 in itself, and one not over consistent with facts (see pp. 51, 52), 



