Its business is in tum subdivided into work performed in a relatively concrete manner in re sponse to individual eillzelne needs and at the request of individurus Einzebzer (the estate of craftsmanship); more abstract work of mass production which supplies individual needs but is more universally in demand (the estate of manujacturers); and the business of exchanging separate commodities Mittel for one another, chiefly through the universal means of exchange, namely money, in which the abstract value of all goods is actualized (the estate ofcommerce).