An instrument of labour is a thing, or a complex of things, which
 the labourer interposes between himself and the subject of his labour,
 and which serves as the conductor of his activity. He makes use of the 175mechanical,
 physical, and chemical properties of some substances in order to make other
 substances subservient to his aims. [2] Leaving out of
 consideration such ready-made means of subsistence as fruits, in gathering
 which a man’s own limbs serve as the instruments of his labour, the first
 thing of which the labourer possesses himself is not the subject of labour
 but its instrument. Thus Nature becomes one of the organs of his activity,
 one that he annexes to his own bodily organs, adding stature to himself
 in spite of the Bible. As the earth is his original larder, so too it is
 his original tool house. It supplies him, for instance, with stones for
 throwing, grinding, pressing, cutting, &c. The earth itself is an instrument
 of labour, but when used as such in agriculture implies a whole series
 of other instruments and a comparatively high development of labour. [3]
 No sooner does labour undergo the least development, than it requires specially
 prepared instruments. Thus in the oldest caves we find stone implements
 and weapons. In the earliest period of human history domesticated animals,
 i.e., animals which have been bred for the purpose, and have undergone
 modifications by means of labour, play the chief part as instruments of
 labour along with specially prepared stones, wood, bones, and shells. [4]
 The use and fabrication of instruments of labour, although existing in
 the germ among certain species of animals, is specifically characteristic
 of the human labour-process, and Franklin therefore defines man as a tool-making
 animal. Relics of bygone instruments of labour possess the same importance
 for the investigation of extinct economic forms of society, as do fossil
 bones for the determination of extinct species of animals. It is not the
 articles made, but how they are made, and by what instruments, that enables
 us to distinguish different economic epochs. [5] Instruments
 of labour not only supply 176a standard of the degree of development
 to which human labour has attained, but they are also indicators of the
 social conditions under which that labour is carried on. Among the instruments
 of labour, those of a mechanical nature, which, taken as a whole, we may
 call the bone and muscles of production, offer much more decided characteristics
 of a given epoch of production, than those which, like pipes, tubs, baskets,
 jars, &c., serve only to hold the materials for labour, which latter
 class, we may in a general way, call the vascular system of production.
 The latter first begins to play an important part in the chemical industries.