have been used as ornament. Pieces of quartz and sandstone, rudely square but with broken corners, from four to five centimeters in diameter and one and a half to two centimeters thick, rubbed down by friction, have been found.[294] +145. Intragroup money from property; intergroup money from trade.+ These cases already show us the distinction between intragroup money and intergroup money. The effect of trade is to develop one or more predominant wares. In the intragroup exchanges this is an object of high desire to individuals for use. It may be an amulet ornament, or a thing of great use in the struggle for existence, e.g. cattle, or a thing of universal acceptance by which anything can be obtained. In intergroup trade it is the chief object of export, the thing for which the trade is carried on, e.g. salt, metal, fur. If this commodity is not easily divisible, the money is something which can be given "to boot," e.g. tobacco, sugar, opium, tea, betel.[295] That is money which will "pass." This does not mean that which can be forced to pass ("legal tender"), but that which will go without force. Amulet ornaments may be either a whim which does not take, or fashion may seize upon something of this kind and make it a tribe mark. Then it becomes group money, because it is universally desired. The articles admit of accumulation, and ostentation is a new joy; they also admit of change and variety. They are available for gifts to the medicine man (to satisfy ghosts, get rain, or thwart disease). They may be used to buy a wife, or to buy a step in the secret society of the men, or to pay a fine or penalty to the chief. The differentiation of goods starts emotion on the line of least resistance, and the predominant goods are the ones of widest demand. Often the predominant ware has a gain from taboo, probably on account of relation to the dead.[296] A thing which is rare and hard to get may become intragroup money. In Fiji the teeth of the spermaceti whale are taken as a measure of value and sign of peace. In German New Guinea the bent tusks of a boar are used as money. In California red birds' heads are used in the same way. Trophy skulls of birds and beasts become a store of wealth, and money with which trade can be carried on with neighbors.[297] The first step seems to be to use the predominant article as the third term of reference in barter. Intergroup money is really a ware and so remains, as gold is now; but groups widen as communication improves, and group money gets a very wide range. In intergroup affairs, therefore, the relations sooner become impersonal and mechanical. The things which are best for this purpose become mobile. Some are better as stores of value, others as means of power, others as measures of value. The last are on the way to become money. The others are more like gems. Thus group money arose from property; intergroup money from trade.