124 MODERN MONETARY SYSTEMS 
Now ought we to deprecate our ignorance on this 
point ? Some economists are of this opinion, and, like IM. 
Rist, after noting the enigma contained in the experience 
of Czechoslovakia and some others, cling in desperation 
to the Quantity Theory, “without which the principal 
stages in the history of prices would remain incom- 
prehensible.”’? 
From the above account it would seem, on the contrary, 
that we can retain enough of the theory to explain these 
important historical events, without rejecting, a priori, 
other factors which may also serve, and sometimes even 
suffice, to make them comprehensible. But we believe, 
on the other hand, that there is nothing but harm in trying 
to invent theories which are more rigid than the facts 
themselves. We shall see that the chief monetary problems 
come down to exchange problems in which it is not the 
abstract Quantity Theory which plays a part, but the 
supply and demand of an external currency by holders of 
an internal one under circumstances which vary as between 
one country and another and one period and another, 
according to the legal conditions and actual circumstances 
which determine the working of the monetary system. 
And we shall observe that the Quantity Theory, so far 
from making easier the solution of these problems, has 
long been instrumental in discarding exact and reasonable 
explanations in favour of superficial and unreal ones. 
1 “La déflation en pratique,” p. 96.