[Cf. _Tao Te Ching_, ch. 30: "Where troops have been quartered, brambles and thorns spring up. Chang Yu has the note: "We may be reminded of the saying: ‘On serious ground, gather in plunder.’ Why then should carriage and transportation cause exhaustion on the highways?—The answer is, that not victuals alone, but all sorts of munitions of war have to be conveyed to the army. Besides, the injunction to ‘forage on the enemy’ only means that when an army is deeply engaged in hostile territory, scarcity of food must be provided against. Hence, without being solely dependent on the enemy for corn, we must forage in order that there may be an uninterrupted flow of supplies. Then, again, there are places like salt deserts where provisions being unobtainable, supplies from home cannot be dispensed with."]