212 Life on the Earthy its Origin and Succession, 



nature from those which are preserved. It follows, therefore, that the 

 earlier living progenitors of the Cambro-Silurian series, not only lived 

 long before but must have lived somewhere else. But as in all the 

 known examples of this series of strata, wherever found, we have every- 

 where animals of the same general type, and nowhere the traces of 

 earlier progenitors, it is clear that everywhere we are required by the 

 hypothesis to look somewhere else ; which may fairly be interpreted to 

 signify, that the hypothesis everywhere fails in the first and most impor- 

 tant step. How is it conceivable that the second stage should be every- 

 where preserved, but the first nowhere ? 



" This difficulty occurs again and again, not only at the great breaks 

 of the series of strata accompanied with much disturbance and change 

 of sea-bed, but during the ordinary and least interrupted accumulations 

 of deposit, for example, in the Silurian and Oolitic systems, in each of 

 which new families and genera, new types of structure in short, make 

 their appearance frequently at definite stages, and always compel the 

 hypothesis to the same answer — look elsewhere for the progenitor — the 

 father is never buried with his children. 



" Is there not at the base of all these hypotheses of one continuously 

 branching stream of variable life, some trace of the common errors of 

 assuming that to be true without limits, which is acknowledged to be 

 true in a restricted sense ; of employing infinite time to integrate quan- 

 tities which are subject to no law of varying magnitude ; and of assign- 

 ing a resultant to unknown and inconstant directions? Do we not 

 find the 'mutability of species' illustrated by examples of limited 

 change, effected by the directing agency of man ; and then what stands 

 for an inference that unlimited changes have been effected or are in 

 progress by the undirected combination of external conditions? Are we 

 sure that varieties which are given by nature in successive generations, 

 can be summed in one direction by the variable preponderant of a num- 

 ber of concomitant variable conditions of life ? Can we remove ' natural 

 selection ' from the large synonymy of * chance,' except by giving to 

 one of the variable conditions of which it is the sum, direction, definite 

 value or effect ? Is it not the one acknowledged possession by every 

 species of an inherent tendency to propagate its like? Would not the 

 effect of this one constant among any number of variables without law, 

 be to preserve the characters of the species for ever ? And if ' natural 

 selection' were regarded as giving direction to these variables, in com- 

 bination with that constant tendency, what would be the final result 

 but that which has always been recognized, viz. a species varying 

 within limits which are to be sought out by experience ? But, finally, if 

 Natural Selection be thus gifted with the power of continually acting 

 for the good of its subject — encouraging it, or rather compelling it to 

 continued advancement, — 



Atei apttTTeveiv Koi vvepjuopou ffifievai ^\\a»i', 



how is this beneficent personification to be separated from an erer 

 watchful providence ; which once brought in to view sheds a new light 

 over the whole picture of causes and effects ? 



