If it is right, as one of our most acute thinkers says, to declare that mankind has placed his tools between himself and the animal world, then another proposition follows directly from this, namely, that man has placed property between himself and animals. It is true that the animal develops as far as the family, for if this also is founded merely upon thought, it cannot be a conscious one. Property presupposes a definite mental equipment, which even in the case of primitive men must be important, implying subjectively an already clear consciousness of self; objectively a certain capacity for measuring even the remoter consequences of an action; for the desire for special possession could only exist with reference to a pronounced consciousness of the self, and to the recognised purpose and further utility of an object. Neither of these mental presuppositions are anywhere fulfilled in the animal world. It need hardly be mentioned that labour in the technical sense has developed naturally and gradually from physiological labour and the bodily functions; that is, that even between the natural implement and the artificial there is no hiatus. Espinas says (_Animal Communities_, by A. Espinas, p. 338): "Every living being, however lonely its life may be, can in case of need build itself some protective covering, and that is the beginning of the artistic impulse (_Kunst-trieb_), unless, perhaps, this is to be found in the formation of the organism itself. Leaving out of consideration the tubicolous annelidae, the mussels and stone-boring molluscs, the weaving caterpillars, and finally spiders, even the non-social hymenoptera present, among many insects, examples of a very skilful adaptation of materials. But it is equally undeniable that, since the appearance of communities whose purpose is the rearing of their offspring, the artistic tendency receives a considerable impulse and produces unexpected marvels. Here it decidedly abandons its usual procedure in order to take up a new one. Hitherto the lower animals have, to a great extent, taken the materials for their places of refuge and their implements from their own bodies: the former an extension of the organism that produces it; the latter, as in the case of the spider, only an enlargement of the animal itself which forms the centre. The productions of the social artistic impulse, on the other hand, are made out of materials which are more and more foreign to the substance of the artificer, and are worked up externally by means which become more and more exclusively mechanical. Hence it follows that the living body is no longer so directly interested in the preservation of its work; it can alter and again build up this structure to an almost infinite extent--in short, the structure becomes more and more an implement instead of an organ. That was the inevitable result of animal life, which, being essentially capable of transference, and presupposing an intercourse of several separate