It is not at all uncommon for a victorious Army to lose many more by sickness than on the field of battle.
If, therefore, we look at this sphere of destruction in Strategy in the same manner as we have considered that of fire and close combat in tactics, then we may well imagine that everything which comes within its vortex will, at the end of the campaign or of any other strategic period, be reduced to a state of weakness, which makes the arrival of a fresh force decisive.

We might therefore conclude that there is a motive in the one case as well as the other to strive for the first success with as few forces as possible, in order to keep up this fresh force for the last.
In order to estimate exactly this conclusion, which, in many cases in practice, will have a great appearance of truth, we must direct our attention to the separate ideas which it contains.

In the first place, we must not confuse the notion of reinforcement with that of fresh unused troops.

There are few campaigns at the end of which an increase of force is not earnestly desired by the conqueror as well as the conquered, and indeed should appear decisive; but that is not the point here, for that increase of force could not be necessary if the force had been so much larger at the first.

But it would be contrary to all experience to suppose that an Army coming fresh into the field is to be esteemed higher in point of moral value than an Army already in the field, just as a tactical reserve is more to be esteemed than a body of troops which has been already severely handled in the fight.