THEORY OF SOIL FERTILITY 181 



not only to increase fertility, but even to main- 

 tain the fertility that has made these acres 

 valuable heretofore. 



When we come to search for parallels to the 

 gold mine example, we actually do not find 

 them in farm valuations, except in the rare in- 

 stances of naturally unproductive lands. Such 

 instances are so remote from this consideration 

 of the subject that they need not be reckoned 

 with at all. On the other hand, while the rank 

 and file of scientists agree and here we should 

 accept the rural scientists as we accept the 

 mining engineers while the rank and file of 

 the orthodox scientists agree that our farm 

 land is slowly and inevitably declining in native 

 fertility, the price of that same farm land ad- 

 vances steadily. Land is better as collateral 

 to-day than it was yesterday. 



There are coming to be exceptions, it is 

 true bankers, for instance, who listen to the 

 theory of Liebig and demand that the farmer 

 feed his soil, return to it as much as he takes 

 away, before he can raise a loan with land as 

 security. I have before me now a paper by 

 a banker of the Middle West, who demands 

 such a system. He offers the farmers of his 

 neighborhood loans on their land, providing 



