24 DEGENERATION : I 



not then been brought into existence, whilst other 

 most strange and varied forms occupied their place, 

 and have now for long ages been extinct. 



Whilst we are thus justified by the direct testi- 

 mony of fossil remains in accounting for some living 

 forms on the hypothesis that their peculiar conditions 

 of life have been such as to maintain them for an 

 immense period of time in statu quo unchanged, we 

 have no reason for applying this hypothesis, and this 

 only, to the explanation of all the more imperfectly 

 organised forms of animal or plant life. 



It is clearly enough possible for a set of forces 

 such as we sum up under the head " natural selec- 

 tion " to so act on the structure of an organism as 

 to produce one of three results, namely, these : to 

 keep it in statu quo ; to increase the complexity of 

 its structure ; or lastly, to diminish the complexity 

 of its structure. We have as possibilities either 

 BALANCE, or ELABORATION, or DEGENERATION. 



Owing, as it seems, to the predisposing influence 

 of the systems of classification in ascending series 

 proceeding steadily upwards from the "lower" or 

 simplest forms to the "higher" or more complex 

 forms, systems which were prevalent before the 

 doctrine of transformism had taken firm root in the 

 minds of naturalists, there has been up to the present 

 day an endeavour to explain every existing form of 

 life on the hypothesis that it has been maintained 

 for long ages in a state of Balance; or else on 

 the hypothesis that it has been Elaborated, and is 

 an advance, an improvement, upon its ancestors. 



