138 ORIGIN OF SPECIES 



Finally, I believe that many lowly organised forms now 

 exist throughout the world, from various causes. In some 

 cases variations or individual differences of a favorable na- 

 ture may never have arisen for natural selection to act on and 

 accumulate. In no case, probably, has time sufficed for the 

 utmost possible amount of development. In some few cases 

 there has been what we must call retrogression of organisa- 

 tion. But the main cause lies in the fact that under very 

 simple conditions of life a high organisation would be of no 

 service, — possibly would be of actual disservice, as being of 

 a more delicate nature, and more liable to be put out of order 

 and injured. 



Looking to the first dawn of life, when all organic beings, 

 as we may believe, presented the simplest structure, how, it 

 has been asked, could the first steps in the advancement or 

 differentiation of parts have arisen? Mr. Herbert Spencer 

 would probably answer that, as soon as simple unicellular 

 organism came by growth or division to be compounded of 

 several cells, or became attached to any supporting surface, 

 his law "that homologous units of any order became differ- 

 entiated in proportion as their relations to incident forces 

 became different" would come into action. But as we have 

 no facts to guide us, speculation on the subject is almost use- 

 less. It is, however, an error to suppose that there would 

 be no struggle for existence, and, consequently, no natural 

 selection, until many forms had been produced: variations 

 in a single species inhabiting an isolated station might be 

 beneficial, and thus the whole mass of individuals might be 

 modified, or two distinct forms might arise. But, as I re- 

 marked towards the close of the Introduction, no one ought 

 to feel surprise at much remaining as yet unexplained on 

 the origin of species, if we make due allowance for our pro- 

 found ignorance on the mutual relations of the inhabitants 

 of the world at the present time, and still more so during 

 past ages. 



CONVERGENCE OF CHARACTER 



Mr. H. C. Watson thinks that I have overrated the im- 

 portance of divergence of character (in which, however, he 

 apparently believes), and that convergence, as it may be 



