XL] SPECIFIC GENESIS. 257 



have, however, had the effect of convincing him that that 

 theory, as the one or as the leading explanation of the 

 successive evolution and manifestation of specific forms, 

 is untenable. At the same time he admits fully that 

 " Natural Selection" acts, and must act, and that it plays 

 in the organic world a certain though a secondary and 

 subordinate part. 



The one modus operandi yet suggested having been found 

 insufficient, the question arises : Can another be substi- 

 tuted in its place ? If not, can anything that is positive, 

 and if anything, what, be said as to the question of specific 

 origination ? 



Now in the first place, it is of course axiomatic that the 

 laws which conditioned the evolution of extinct and of 

 existing species are of as much efficacy at this moment as 

 at any preceding period, that they tend to the manifesta- 

 tion of new forms as much now as ever before. It by no 

 means necessarily follows, however, that this tendency 

 is actually being carried into effect, and that new species 

 of the higher animals and plants are now being pro- 

 duced. They may be so or they may not, according as 

 existing circumstances favour, or conflict with, the action 

 of those laws. It is possible that lowly organized creatures 

 may be continually evolved at the present day, the requisite 

 conditions being more or less easily supplied. There is, 

 however, no such evidence at present as to higher forms ; 

 while, as we have seen in Chapter VII., there are a priori 

 considerations which militate against their being similarly 

 evolved. 



The presence of wild varieties, and the difficulty which 

 often exists in the determination of species, are sometimes 

 adduced as arguments that high forms are now in process 



