Or, bringing in the word species, which is well defined as “the perennial succession of individuals,” commonly of very like individuals,—­as a close corporation of individuals perpetuated by generation, instead of election,—­and reducing the question to mathematical simplicity of statement:  species are lines of individuals coming down from the past and running on to the future,—­lines receding, therefore, from our view in either direction.  Within our limited view they appear to be parallel lines, as a general thing neither approaching to nor diverging from each other.  The first hypothesis assumes that they were parallel from the unknown beginning and will be to the unknown end.  The second hypothesis assumes that the apparent parallelism is not real and complete, at least aboriginally, but approximate or temporary; that we should find the lines convergent in the past, if we could trace them far enough; that some of them, if produced back, would fall into certain fragments of lines, which have left traces in the past, lying not exactly in the same direction, and these farther back into others to which they are equally unparallel.  It will also claim that the present lines, whether on the whole really or only approximately parallel, sometimes fork or send off branches on one side or the other, producing new lines, (varieties,) which run for a while, and for aught we know indefinitely, when not interfered with, near and approximately parallel to the parent line.  This claim it can establish; and it may also show that these close subsidiary lines may branch or vary again, and that those branches or varieties which are best adapted to the existing conditions may be continued, while others stop or die out.  And so we may have the basis of a real theory of the diversification of species; and here, indeed, there is a real, though a narrow, established ground to build upon.  But, as systems of organic Nature, both are equally hypotheses, are suppositions of what there is no proof of from experience, assumed in order to account for the observed phenomena, and supported by such indirect evidence as can be had.  Even when the upholders of the former and more popular system mix up revelation with scientific discussion,—­which we decline to do,—­they by no means thereby render their view other than hypothetical.  Agreeing that plants and animals were produced by Omnipotent fiat does not exclude the idea of natural order and what we call secondary causes.  The record of the fiat—­“Let the earth bring forth grass, the herb yielding seed,” etc., “and it was so”; “let the earth bring forth the living creature after his kind, cattle and creeping thing and beast of the earth after his kind, and it was so”—­seems even to imply them.  Agreeing that they were formed of “the dust of the ground” and of thin air only leads to the conclusion that the pristine individuals were corporeally constituted like existing individuals, produced through natural agencies.  To agree that they were created “after their kinds” determines nothing as to what were the original kinds, nor in what mode, during what time, and in what connections it pleased the Almighty to introduce the first individuals of each sort upon the earth.  Scientifically considered, the two opposing doctrines are equally hypothetical.