LEADING FEATURES OF THE WHEAT INDUSTRY 215 
relieved the most serious effects of the greatest depression 
the country has ever passed through, and was instru- 
mental in changing the whole aspect of rural life. Prior 
to this, two lines of policy were open to the farmer. He 
had to be either a cultivator, or a pastoralist herding 
relatively few sheep for the sake of their wool. Now, 
however, there is a middle course. It is expedient and 
often necessary to combine these two formerly separate 
lines of action into one, now that the freezing industry 
is established. Thus arose the system of ‘‘mixed farm- 
ing,’’ under which pastoral and agricultural pursuits are 
carried on together. The relative advantages of this 
system have been discussed in Chapter III., and men- 
tioned in other parts of this work; but an interesting 
line of discussion from the point of view of organisation 
at once suggests itself. 
Under this system the farmer’s interests are two-fold; 
he is combining two lines of action which are independent 
of each other, from the point of view of immediate 
profits, and yet are so connected that successful co- 
operation will greatly enhance profits on the whole. The 
question then arises, what principle controls the farmer 
in his attitude to these two lines of action? What factor, 
or set of factors, guides his choice of the relative extent 
to which he will follow out these lines of action? 
The farmer, again consciously or otherwise, is being 
guided in his actions by certain economic forces, and is 
working in accordance with a principle which is an 
indirect deduction from the predominating economic 
force of self-interest. Each occupation will be pursued 
to the point to which any further energy spent in it will 
produce a relatively smaller rate of profit than that 
obtained by the last unit of energy spent in any other 
occupation. This is the principle of equi-marginal returns, 
and it is to this principle that we must look if we would 
