Nowadays the circumstances are quite changed. It is out of the question for the horses of the modern army to find the necessary forage in the country itself. That the men of the great armies of the present day can supply themselves when rations run out remains to be proved. On paper it is indeed often possible, taking into consideration the supplies available in peace; but these calculations cannot hold good for a real theatre of war where concentration has claimed all available resources. Of the straits to which a great army may be reduced when supplies really give out, the campaign of 1812 in Russia is a good example. There, even during the advance to Moscow, Napoleon's army practically dissolved owing to lack of supplies. Only some 90,000 men of the mighty host arrived in Moscow; only these perished during the retreat. How fearfully the Napoleonic armies suffered and melted away owing to want of supplies gives cause for reflection. In the armies of millions of the present day such conditions become still more perilous. Matters appertaining to ammunition are of equal importance. The modern army carries enormous masses of artillery with it. All the guns are designed for a vast expenditure of ammunition, and the _rafale_ from covered positions and against covered positions will indeed make this necessary. Modern infantry, too, is armed in a manner that will entail a prodigious expenditure of cartridges. The replacement of this expended ammunition is of vital importance. Railways will have to be laid in rear of the armies to cope with these demands. Long trains of wagons and automobiles will move to and fro behind them. On every high-road and in every railway-station magazines will appear, and all operations must come to a standstill and miscarry as soon as this great organisation ceases from any cause to carry out its functions. I hold, therefore, that such circumstances render a disturbance of the rear communications of an army an important matter. It will often do the opponent more damage, and contribute more to a favourable decision of arms than the intervention of a few cavalry divisions in the decisive battle itself.