To the poisonous effluvia of these marshes the Doctor attributes, in an especial manner, the plagues which took place in the armies. In the second year of the Peloponnesian war, the Athenian army was encamped, as we are told by Thucydides, “upon marshy and unwholesome ground;” and that such kind of encampments will produce diseases in an army is well known. In the time of Dionysius, when the Carthaginian army under Imilco suffered so dreadfully, or rather was totally destroyed, his camp was situated on an eminence between two morasses, the heat at that time being excessive. Hannibal, the predecessor of Imilco, had also lost great part of his army by a plague, though he had been encamped in a healthy situation; but, in order to raise a wall which should overlook the city, he had taken the materials of the tombs found in the common burial place, the city at that time containing two hundred thousand inhabitants. “From the uncovering and disturbing of so many dead bodies (says our author) arose a terrible pestilence, which carried off immense numbers of the Carthaginians, and amongst the rest the general himself.” To the unhealthy situation of the armies also the Doctor ascribes the plague which took place in the Roman and Carthaginian camps in the time of the second punic war; and the Carthaginians suffered most, by reason of their being nearer to the marshes. The state of mind, the cleanliness of the person, &c. also must be taken into account; and our author shows that neither of these could be supposed favourable to the Carthaginians. That personal cleanliness, and breathing pure air, should contribute to the health of individuals, or to any number of them collected into camps or cities, seems to be agreeable to reason and common sense; nevertheless we find that this has been denied, and even Dr. Canestrinus says that “in the plague of Lyons and Marseilles it was observed, that the most populous parts of these cities, _where the streets were narrow and filthy_, suffered _less_ from the disease than those which were more airy and clean. At the time of the plague in London in the time of Charles II, the physicians advised that all the _privies_ should be opened and exposed; the fetid odour from which having pervaded the city, the plague was stopped! Is it from this cause (the author asks) that the plague has seldomer visited Spain, the towns of which are intolerably offensive from their want of cleanliness?”[114] [114] Medical Review, vol. iii, p. 260.