On Aquatic Carnivorous Coleoptera or Dijtiscidce. 189 



far reaching and enduring law — the transition must have been long enduring in 

 time and wide spread in space. Can we believe it possible that universal law 

 should have resulted in the production of a single inconceivably minute portion of 

 organic matter, from which all the enormous aggregate of organisms now around 

 us has been produced in its almost unthinkable variety by a process of simple 

 reproduction? No, I think that whatever the mode or modes may have been by 

 which inorganic matter became organic, it will surely prove more credible that 

 the passage extended over a vast period of time, and occurred in numerous places, 

 and was not limited to one instant of time and a single pin point of space. It 

 we say this we admit that it is possible that there have existed distinctions in 

 the individual masses of oi"ganic beings from their very beginnings, and it is 

 quite conceivable that in these aboriginal molecular diflerences may have 

 originated the present physiological species distinctions, — that these are in tact 

 absolute and direct continuations of primeval molecular ditferences of constitution ; 

 and it is credible that from such a myriad beginning, through the enormous ages 

 of the woi'ld there have developed the vast multitudes of species of plants and 

 animals amongst which we live. If anything like this has been true, we need 

 not necessarily adopt any theory of community of descent, but we may believe 

 that each species is a distinct record of the past conditions in which it has existed, 

 and that resemblance in structure of two different species is the result of similar 

 growth under similar conditions. 



I shall not at present allude farther to the difficulties that surround the theory 

 of community of descent, but I may remark that even if it should prove that we 

 must abandon the hope of tracing the pedigree of all creatures back to a single 

 organism, this in nowise detracts from the importance of biology. We are not 

 called on to abandon the attempt to understand the relations between existing 

 and extinct morphological forms, species by species, and to trace the road by which 

 existing structures have become what we see them. The theory of evolution is in 

 no way connected with the hypothesis of common descent ; and by means of the 

 perfected acquaintance with the structures of existing organisms we shall attain, and 

 of the detailed knowledge we shall acquire of the special modifications that have 

 taken place in myriad separate lines of descent on various parts of the earth's 

 surface, we may well hope that we shall be able to read slowly but truly the great 

 history of Nature. 



Bates has an admirable remark — (" Naturalist on the Amazons," Vol. II, p. 34.5) 

 speaking of the local variations in the patterns on the wings of butterflies, he has 

 said, " On these expanded membranes Nature writes, as on a tablet, the story of 

 the modifications of species, so truly do all changes of the organization register 

 themselves thereon. " By the evolutionist this sensitiveness thus truly claimed for 

 the butterfly's wing, may logically be asserted to have always existed in all the 

 structures of every species of the organic world. Every individual is a mass of 



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