Yet the fact is that the high rate of exchange and the depredatory U-boat represented almost identically the same danger.

The prospect that so darkened the horizon in the spring of 1917 was the possible isolation of Great Britain.
England's weakness, as always, consisted in the fact that she was an island, that she could not feed herself with her own resources and that she had only about six weeks' supply of food ahead of her at any one time.

If Germany could cut the lines of communication and so prevent essential supplies from reaching British ports, the population of Great Britain could be starved into surrender in a very brief time, France would be overwhelmed, and the triumph of the Prussian cause would be complete.

That the success of the German submarine campaign would accomplish this result was a fact that the popular mind readily grasped.
What it did not so clearly see, however, was that the financial collapse of Great Britain would cut these lines of communication quite as effectually as the submarine itself.

The British were practically dependent for their existence upon the food brought from the United States, just as the Allied armies were largely dependent upon the steel which came from the great industrial plants of this country.