DARWIN AND HIS REVIEWERS. 135 



established, and may fairly be doubted. We believe 

 that species vary, and that " Natural Selection " 

 works ; but we suspect that its operation, like every 

 analogous natural operation, may be limited by some- 

 thing else. Just as every species by its natural rate of 

 reproduction would soon completely fill any country 

 it could live in, but does not, being checked by some 

 other species or some other condition so it may 

 be surmised that variation and natural selection 

 have their struggle and consequent check, or are 

 limited by something inherent in the constitution of 

 organic beings. 



We are disposed to rank the derivative hypothe- 

 sis in its fullness with the nebular hypothesis, and to 

 regard both as allowable, as not unlikely to prove ten- 

 able in spite of some strong objections, but as not 

 therefore demonstrably true. Those, if any there be, 

 who regard the derivative hypothesis as satisfactorily 

 proved, must have loose notions as to what proof is. 

 Those who imagine it can be easily refuted and cast 

 aside, must, we think, have imperfect or very pre- 

 judiced conceptions of the facts concerned and of 

 the questions at issue. 



We are not disposed nor prepared to take sides for 

 or against the new hypothesis, and so, perhaps, occu- 

 py a good position from which to watch the discus- 

 sion and criticise those objections which are seemingly 

 inconclusive. On surveying the arguments urged by 

 those who have undertaken to demolish the theory, 

 we have been most impressed with a sense of their 

 great inequality. Some strike us as excellent and 

 perhaps unanswerable; some, as incongruous with 



