30 
MONEY 
things have become more plentiful. Therefore, it will 
be suggested, in treating of currency and prices, we 
ought to think just as much about the quantity of 
commodities in general as about the quantity of 
currency. 
The answer to this is that in fact no one thinks it 
necessary in the case of ordinary commodities to insist 
on the fact that their value depends on the absolute 
plentifulness of all other commodities as well as on 
their own absolute plentifulness. The relationship 
between the quantities is the thing we have to con- 
sider, and it is both legitimate and convenient to 
treat of changes in this relationship as if they were 
always caused by changes in the quantity of the thing 
in question, ignoring the possibility of their being 
caused by changes in the quantity of all other things. 
It is legitimate, because it makesno difference to the 
argument whether the change in relationship is 
caused by change in the thing itself or in all the other 
things. It is convenient, because the change in all 
other things is almost always so slow as to be prac- 
tically negligible over such period of time as we are 
likely to be interested in. 
Currency is certainly no exception to the rule. If 
its standard is a metallic one, this is obvious. There 
is no more reason for insisting on the quantity of all 
other things when we are dealing with gold or silver 
than when we are dealing with iron and tin. 
If the standard is a paper unit, the variations in 
the quantity of all other things are likely to be even 
less comparatively important than when it is metallic. 
The “scarcity of commodities” during the war 
was mythical. Production was really very large; 
what happened was that it was diverted into unusual 
channels. The production of a great many important 
articles fell off, but immense quantities of munitions 
of war were produced instead ; many services were