124. The question at issue is, Are the resemblances observable among organic forms due to remote kinship, and their diversities to the divergences caused by adaptation to new conditions? or are the resemblances due to similarities, and the diversities to dissimilarities in the _substance and history_ of organic beings? Are we to assume one starting-point and one centre of creation, or many similar starting-points at many centres? So far from believing that all plants and animals had their origin in one primordial cell, at one particular spot, from which descendants migrated and became diversified under the diverse conditions of their migration, it seems to me more consistent with the principle of Evolution to admit a vast variety of origins more or less resembling each other; and this initial resemblance will account for the similarities still traceable under the various forms; while the _early differences_, becoming intensified by development under different conditions, will yield the diversities. The evolution of organisms, like the evolution of crystals, or the evolution of islands and continents, is determined, 1st, by laws _inherent in the substances evolved_, and, 2d, by relations to the medium in which the evolution takes place. This being so, we may _à priori_ affirm that the resultant forms will have a community strictly corresponding with the resemblance of the substances and their conditions of evolution, together with a diversity corresponding with their differences in substance and conditions. It is usually supposed that the admission of separate “centres of creation” is tantamount to an admission of “successive creations” as interpreted by the majority of those who invoke “creative fiats.” But the doctrine of Evolution, which regards Life as making its appearance _consequent upon a concurrence of definite conditions_, and regards the specific forms of Life as the necessary consequences of special circumstances, must also accept the probability of similar conditions occurring at different times and in different places. Upon what grounds, cosmical or biological, are we to assume that on only _one_ microscopic spot of this developing planet such a group of conditions was found--on only one spot a particle of protein substance was formed out of the abundant elements, and under conditions which caused it to grow and multiply, till in time its descendants overran the globe? The hypothesis that all organic forms are the descendants of a single germ, or of even a few germs, and are therefore united by links of kinship more or less remote, is not more acceptable than the hypothesis that all the carbonates and phosphates, all the crystals, and all the strata found in different parts of the globe, are the _descendants of a single molecule_, or a few molecules; or,--since this may seem too extravagant,--than that the various maladies which afflict organic beings are, in a literal sense, members of _families_ having a nearer