The justice of this method is further supported by another general psychical law of groups. This is, that they attract in the direct ratio of their mass; the more numerous a party is, the more adherents will it obtain. Hence, although in the above example the mean, 450, is less than half of the whole number, yet it is much greater than either of the other three sub-groups, 100, 225, 225, and exerts therefore double the attractive power of the latter. That is, in a question of opinion, it will receive twice as many adherents as either of the latter. Hence the value of majorities as expressing the will of a community. The principle of psychical action on which the above is based is one very familiar to students of psychology. It is that termed “collective suggestion.” This is the overmastering tendency to imitate the examples of others, to act in accordance with the ideas and feelings which we witness in those around us. When such ideas and sentiments are constant, and conspicuously displayed, they overcome resistance and the individual mind is attracted to that of the group with like irresistible magnetism as in fairy lore drew the ship of the mariners to the loadstone rocks of Avalon. From these considerations it will be understood that the group may be regarded mathematically as a “constant,” the resultant of a number of “variables,” the individuals of whom it is constituted. Many writers of late years have spoken of the social unit, the group or the nation, as an “organism.” Some have further defined it as a “super-organism” or a “physio-psychic organism.” Such expressions are well enough as figures of speech. They serve to accentuate the interdependence of parts and the potentiality of change and development in the ethnic mind. But the simile becomes illusory and deceptive when it is set up as a principle from which to deduce conclusions. The group is no more an organism than is any other psychical concept, that of the “genus Homo” for example. A vital characteristic of the ethnic group is the degree of its _centralisation_. This is, in truth, a coefficient of its powers. Numbers may be said to increase thus by addition, but centralisation by multiplication. The centralisation, however, must be real; not simply a single point of action, but also a convergence of forces to that point. The French nation is popularly supposed to be centralised in Paris; but in fact the provinces are usually ignorant of national action there until after it has occurred. It is through modern methods of rapid transmission of intelligence that national groups can act with so much greater force than in earlier days.