G. Since personal services are, as a rule, performed and received only by individuals, the principle in accordance with which labor in general becomes cheaper in the higher stages of civilization, does not apply to them to any great extent.(818) Yet we may claim that advancing civilization has pretty universally a twofold influence on the price paid for personal services. In the first place, freedom of competition, with the more accurate and equitable determination of price which it produces (in contradistinction to servitude, privilege and custom) always tends to obtain the upper hand; and further, by the growing combination of labor and of use (§§ 56, ff. 207), a better and better and more clearly defined gradation between ordinary services and those of a higher order is effected. When the latter cannot be increased at pleasure, the price paid for them may, as the wealth of consumers increases, become, from motives of vanity or of custom (_Gebrauchsgründen_), almost unlimited. The dancing maid, to whom Herod (Mark, 6, 23) promised even the half of his kingdom, is both in a politico-economical and in a moral sense a warning example to over-refined nations.(819) Section CXXXV. History Of The Values Of The Precious Metals.—In Antiquity And In The Middle Ages. It is impossible to write a real history of the values of the precious metals in ancient and medieval times: the sources of information are too few. But it does seem possible to suggest some fragments and something of the development of that history,(820) at least in outline.