ON THE ORIGIN OF GENERA. 43 



law, it is proposed to render bighly probable that the same specific 

 form has existed through a succession of genera, and perhaps in 

 different epochs of geologic time. 



"With regard to the first law of development, as above proposed, 

 no one has found means of discovering it, and perhaps no one ever 

 will. It would answer such questions as this : What necessary- 

 coincidence of forces has resulted in the terminus of the series of 

 fishes in the perches as its most specialized extreme ; or, of the 

 Batracliia, in the fresh- water frogs as its ultimum ; or, of the 

 thrushes, among birds, as their highest extreme : in a word, what 

 necessity resulted in man as the crown of the mammalian series, 

 instead of some other organic type ? Our only answer and law for 

 these questions must be, the will of the Creator. 



The second law, of modes and means, has been represented to 

 be that of natural selection, by Darwin. This is, in brief, that a 

 disposition to a general variation on the part of species has been 

 met by the greater or less adaptation of the results of such varia- 

 tion to the varying necessities of their respective situations. That 

 the result of such conflict has been the extinction of those types 

 that are not adapted to their immediate or changed conditions, 

 and the preservation of those that are. 



In determining those characters of plants and animals which 

 constitute them what they are, we have, among others of higher 

 import, those which constitute them species and those which con- 

 stitute them genera. What we propose is : that, of the latter, 

 comparatively very few in the whole range of animals and plants 

 are adaptations to external needs or forces, and of the former a 

 large proportion are of the same kind. How, then, could they owe 

 their existence to a process regulated by adaptation ? 



Darwin is aware of these facts to some degree, but, as already 

 said, he does not dwell on them. Where he does, he does not at- 

 tempt to account for them on the princij)le of natural selection. 



There are, it appears to us, two laws of means and modes of 

 development : I. The law of acceleration and retardation. II.' 

 The law of natural selection. 



It is my purpose to show that these propositions are distinct, 

 and not one a part of the other : in brief, that, while natural selec- 

 tion operates by the "preservation of the fittest," retardation and 

 acceleration act without any reference to "fitness" at all; that, 

 instead of being controlled by fitness, it is the controller of fitness. 

 Perhaps all the characteristics sujjposcd to mark generalized groups 



