PDF - Wallace Online

ix THE DEBT OF SCIENCE TO DARWIN 453species that now exists or ever has existed on the globe wasknown to involve difficulties and contradictions of the mostserious nature, although it was seen that many of the factsrevealed by comparative anatomy, by embryology, by geographicaldistribution, and by geological succession wereutterly unmeaning and even misleading, in view of it; yet,down to the period we have named, it may be fairly statedthat nine-tenths of the students of nature unhesitatinglyaccepted it as literally true, while the other tenth, thoughhesitating as to the actual independent creation, were nonethe less decided in rejecting utterly and scornfully the viewselaborated by Lamarck, by Geoffroy St. Hilaire, and at amuch later date by the anonymous author of the Vestiges ofCreation that every living thing had been produced by somemodification of ordinary generation from parents more or lessclosely resembling it. Holding such views of the absoluteindependence of each species, it almost necessarily followedthat the only aspect of nature of which we could hope toacquire complete and satisfactory knowledge was that whichregarded the species itself. This we could describe in theminutest detail ;we could determine its range in space andin time; we could investigate itsembryology from therudimental germ, or even from the primitive cell, up to theperfect animal or plant we could learn ; every point in itsinternal structure, and we might hope, by patient researchand experiment, to comprehend the use, function, and modeof action of every tissue and fibre, and ultimately of eachcell and organic unit. All this was real knowledge, was solidfact. But, so soon as we attempted to find out the relationsof distinct species to each other, we embarked on a sea ofspeculation. We could, indeed, state how one species differedfrom another species in every particular of which we hadknowledge but we could draw no sound inferences as to the;reason or cause of such differences or resemblances, except byclaiming to know the very object and meaning of the creatorin producing such diversity. And, in point of fact, the chiefinference that was drawn is now proved to be erroneous. Itwas generally assumed, as almost self-evident, that theultimate cause of the differences in the forms, structures, andhabits of the organic productions of different countries, was