property or resources can attain importance only after the introduction of good money, since, previous to such introduction, it was by reason of its great variety,(697) and of its perishable nature, immensely inferior to landed property. Hence it is, that money, in a nation’s economy, is what the blood is in the life of the animal. It is, so to speak, the common reservoir in which all food is first dissolved, and by which, at a later stage, the elements of nutrition and preservation are distributed to the several organs.(698) There is, indeed, no machine which has saved as much labor as money. (_Lauderdale_). It is true that the shadows which wealth is wont to cast, extravagance, avarice and inequality of every kind, may readily grow longer and darker in consequence of the introduction of money.(699) But may not the knife which, in the hands of the surgeon, does so much for life, become an instrument of danger in the hands of a child? The invention of money has been rightly compared to the invention of writing with letters.(700) We may, however, call the introduction of money as the universal medium of exchange (money-economy),(701) in which goods intended for use are exchanged against money(702)—instead of barter (barter economy), which is a system of public economy (_Schäffle_), in an, as yet, very little developed form, man being there less sociable with his fellow men—one of the greatest and most beneficent advances ever made by the race.(703) Section CXVIII. The Different Kinds Of Money. Very different kinds of commodities have, according to circumstances, been used as money; but uniformly only such as possess a universally recognized economic value.(704) On the whole, people in a low stage of civilization are wont to employ, mainly, only ordinary commodities, such as are calculated to satisfy a vulgar and urgent want, as an instrument of exchange. As they advance in civilization, they, at each step, choose a more and more costly object, for this purpose,(705) and one which ministers to the more elevated wants. A. Races of hunters, at least in non-tropical countries, usually use skins as money; that is the almost exclusive product of their labor, one which can be preserved for a long period of time, which constitutes their principal article of clothing and their principal export in the more highly developed regions.(706) B. Nomadic races and the lower agricultural races,(707) pass, by a natural gradation, to the use of cattle as money; which supposes rich pasturages at the disposal of all. If it were otherwise, there would be a great many to whom payments of this kind had been made, who would not know what to do with the cattle given them, on account of the charges for their maintenance.(708) Section CXIX. The Metals As Money.