134. Having brought together the manifold resemblances, and the no less marked diversities, we must ask what is their significance? Do the resemblances imply a community of origin, an universal kinship? If so, the diversities will be nothing more than the divergences which have been produced by variations in the Life-history of the several groups. Or--taking the alternative view--do the diversities imply radical differences of origin? If so, the resemblances will be nothing more than the inevitable analogies resulting from Organized Substance being everywhere somewhat similar in composition, and similar in certain phases of evolution. To state the former position in the simplest way, we may assume that of two masses of protoplasm having a common parentage, one, by the accident of assimilating a certain element not brought within the range of the other, thereby becomes so differentiated as to form the starting-point of a series of evolutions widely divergent from those possible to its congener; and at each stage of evolution the introduction of a new element (made possible by that stage) will form the origin of a new variation. It is thus feasible to reduce all organic forms to a primordial protoplasm, in the evolutions of which successive differentiations have been established. On the other hand, it is equally feasible to assume that the existence of radical differences must be invoked to account for the possibility of the successive differentiations. 135. The hunt after resemblances has led to much mistaken speculation; and with reference to the topic now before us, it may be urged, that although by attaching ourselves to the points of community, in disregard of the diversities, we may make it appear that all animals have a common parentage, and that plants and animals are merely divergent groups of the same prototype, a rigorous logic will force us onwards, and compel us to admit that a kinship no less real unites the organic with the inorganic world. For upon what principle are we to pause at the cell or protoplasm? If by a successive elimination of differences we reduce all organisms to the cell, we must go on and reduce the cell itself to the chemical elements out of which it is constructed; and inasmuch as these elements are all common to the inorganic world, the only difference being one of synthesis, we reach a result which is the stultification of all classification, namely, the assertion of a kinship which is universal. We must bear in mind that all things may be reduced to a common root by simply disregarding their differences. All things are alike when we set aside their unlikeness.