CREATION AND EVOLUTION. 819 



can be proved, in an}^ case, is that no known natural 

 cause is competent to produce a given effect ; and it is 

 an obvious blunder to confound the demonstration of our 

 own ignorance with a proof of the impotence of natural 

 causes. However, apart from the philosophical worth- 

 lessness of the hypothesis of creation, it would be a waste 

 of time to discuss a view which no one upholds. And, 

 unless I am greatly mistaken, at the present day, no 

 one possessed of knowledge sufficient to give his opinion 

 importance is prepared to maintain that the ancestors of 

 the various species of crayfish were fabricated out of in- 

 organic matter, or brought from nothingness into being, 

 by a creative fiat. 



Our only refuge, therefore, appears to be the hypo- 

 thesis of evolution. And, with respect to the doctrine 

 of abiogenesis, we may also, in view of a proper 

 economy of labour, postpone its discussion until such 

 time as the smallest fragment of evidence that a craj^finh 

 can be evolved by natural agencies from not living matter, 

 is brought forward. 



In the meanwhile, the hypothesis of transformism 

 remains in possession of the field ; and the only pro- 

 fitable inquiry is, how far are the facts susceptible of 

 interpretation, on the hypothesis that all the existing 

 kinds of crayfish are the product of the metamorphosis 

 of other forms of living beings ; and that the bio- 

 logical phenomena which they exhibit are the results 

 of the interaction, through past time, of two series of 



