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less significant relations joining on Ethics to more inde- pendent sciences, aesthetics, for example. This, or some similar plan, is obviously required, if classification is to be that help to the understanding which it is capable of becoming. But if this be so with respect to such a subject as the grouping of the sciences, much more is it so with Biological classification. The resemblances between groups both of animals and of plants are almost infinite, and no pains should be spared to bring out as many of them as is possible. The foundation of a natural group indeed is number and persistence of characters, and how can this be secured ex- cept by copious regrouping? How else can the mind be adequately helped in its effort to grasp the phenomena ? Moreover, these regroupings, in order to be duly effective, must be accompanied by schematic devices, chief of which is the Table. It is only by such means that the mind can be fully impressed with the unity that exists in the midst of variety throughout the world of animate beings ; and only by such means can our view both of the whole and of the parts become clear and definite. As, however, this is a subject that I have already handled in an article on " Botanical Classification " in MIND 20, I shall not here dwell upon it. Sufficient to have noted it, and to have called attention afresh to its character and importance. IV. A question, however, now presents itself. If it is the fact that complicated classifications need a system of grouping and regrouping, does not this tell against the logical charac- ter of the process altogether ? No doubt, to some extent it does. For, it is an admission that the groups are not at all points and in every way mutually exclusive, that, in a greater or a less degree, there is overlapping. But it is important to observe of what kind the overlapping is. Take the classification of the sciences, and it is seen that the process begins at its widest sweep with a pure dichotomous division : it is the contrast of the Abstract and the Concrete. Similarly, the kingdom of animals at its highest grade is divided into Vertebrates and Invertebrates ; and the kingdom of plants into Flowering and Flowerless. So, the systematic arrangement of duties, in Ethics, proceeds upon the opposi- tion of Egoistic and Altruistic ; and any proper treatment of the Emotions must pay due regard to the dominant con- trast of Disinterestedness and Malevolence. It is in filling