We have therefore a right to exclude them as well as the other preparatory activities from the Art of War in its restricted sense, from the conduct of War properly so called; and we are obliged to do so if we would comply with the first principle of all theory, the elimination of all heterogeneous elements.

Who would include in the real "conduct of War" the whole litany of subsistence and administration, because it is admitted to stand in constant reciprocal action with the use of the troops, but is something essentially different from it?
We have said, in the third chapter of our first book, that as the fight or combat is the only directly effective activity, therefore the threads of all others, as they end in it, are included in it.

By this we meant to say that to all others an object was thereby appointed which, in accordance with the laws peculiar to themselves, they must seek to attain.

Here we must go a little closer into this subject.
The subjects which constitute the activities outside of the combat are of various kinds.
The one part belongs, in one respect, to the combat itself, is identical with it, whilst it serves in another respect for the maintenance of the military force.

The other part belongs purely to the subsistence, and has only, in consequence of the reciprocal action, a limited influence on the combats by its results.