The Prairie Traveler: A Hand-book for Overland Expeditions

by Randolph B. Marcy

"The fact is the reverse; but, demonstrative as the fact may be, fashion has more influence than multiplied examples of fact experimentally proved. Encampments are still formed in the vicinity of swamps, or on grounds which are newly cleared of their woods, in obedience to theory, and contrary to fact.

"It is prudent, as now said, in selecting ground for encampment, to avoid the immediate vicinity of swamps and rivers. The air is there noxious; but, as its influence thence originating does not extend beyond a certain limit, it is a matter of some importance to ascertain to what distance it does extend; because, if circumstances do not permit that the encampment be removed out of its reach, prudence directs that remedies be applied to weaken the force of its pernicious impressions.

"The remedies consist in the interposition of rising grounds, woods, or such other impediments as serve to break the current in its progress from the noxious source. It is an obvious fact, that the noxious cause, or the exhalation in which it is enveloped, ascends as it traverses the adjacent plain, and that its impression is augmented by the adventitious force with which it strikes upon the subject of its action.

"It is thus that a position of three hundred paces from the margin of a swamp, on a level with the swamp itself, or but moderately elevated, is less unhealthy than one at six hundred on the same line of direction on an exposed height. The cause here strikes fully in its ascent; and as the atmosphere has a more varied temperature, and the succussions of the air are more irregular on the height than on the plain, the impression is more forcible, and the noxious effect more strongly marked. In accord with this principle, it is almost uniformly true, cœteris paribus, that diseases are more common, at least more violent, in broken, irregular, and hilly countries, where the temperature is liable to sudden changes, and where blasts descend with fury from the mountains, than in large and extensive inclined plains under the action of equal and gentle breezes only.

"From this fact it becomes an object of the first consideration, in selecting ground for encampment, to guard against the impression of strong winds on their own account, independently of their proceeding from swamps, rivers, and noxious soils.

"It is proved by experience, in armies as in civil life, that injury does not often result from simple wetting with rain when the person is fairly exposed in the open air, and habitually inured to the contingencies of weather. Irregular troops, which act in the advanced line of armies, and which have no other shelter from weather than a hedge or tree, rarely experience sickness—never, at least, the sickness which proceeds from contagion; hence it is inferred that the shelter of tents is not necessary for the preservation of health. Irregular troops, with contingent shelter only, are comparatively healthy, while sickness often rages with violence in the same scene, among those who have all the protection against the inclemencies of weather which can be furnished by canvas. The fact is verified by experience, and the cause of it is not of difficult explanation. When the earth is damp, the action of heat on its surface occasions the interior moisture to ascend. The heat of the bodies of a given number of men, confined within a tent of a given dimension, raises the temperature within the tent beyond the temperature of the common air outside the tent. The ascent of moisture is thus encouraged, generally by a change of temperature in the tent, and more particularly by the immediate or near contact of the heated bodies of the men with the surface of the earth. Moisture, as exhaled from the earth, is considered by observers of fact to be a cause which acts injuriously on health. Produced artificially by the accumulation of individuals in close tents, it may reasonably be supposed to produce its usual effects on armies. A cause of contagious influence, of fatal effect, is thus generated by accumulating soldiers in close and crowded tents, under the pretext of defending them from the inclemencies of the weather; and hence it is that the means which are provided for the preservation of health are actually the causes of destruction of life.

"There are two causes which more evidently act upon the health of troops in the field than any other, namely, moisture exhaled direct from the surface of the earth in undue quantity, and emanations of a peculiar character arising from diseased action in the animal system in a mass of men crowded together. These are principal, and they are important. The noxious effects may be obviated, or rather the noxious cause will not be generated, under the following arrangement, namely, a carpet of painted canvas for the floor of the tent; a tent with a light roof, as defense against perpendicular rain or the rays of a vertical sun; and with side walls of moderate height, to be employed only against driving rains. To the first there can be no objection: it is useful, as preventing the exhalations of moisture from the surface of the earth; it is convenient, as always ready; and it is economical, as less expensive than straw. It requires to be fresh painted only once a year."

The effect of crowding men together in close quarters, illy ventilated, was shown in the prisons of Hindostan, where at one time, when the English held sway, they had, on an average, 40,000 natives in confinement; and this unfortunate population was every year liberated by death in proportions varying from 4000 to 10,000. The annual average mortality by crowded and unventilated barracks in the English army has sometimes been enormous, as at Barrackpore, where it seldom fell far short of one tenth; that is to say, its garrisons were every year decimated by fever or cholera, while the officers and other inhabitants, who lived in well-ventilated houses, did not find the place particularly unhealthy.

The same fact of general exemption among the officers, and complete exemption among their wives, was observed in the marching regiments, which lost by cholera from one tenth to one sixth of the enlisted men, who were packed together at night ten and twelve in a tent, with the thermometer at 96°. The dimensions of the celebrated Black Hole of Calcutta—where in 1756, 123 prisoners out of 140 died by carbonic acid in one night—was but eighteen feet square, and with but two small windows. Most of the twenty-three who survived until morning were seized with putrid fever and died very soon afterward.

On the 1st of December, 1848, 150 deck passengers of the steamer Londonderry were ordered below by the captain and the hatches closed upon them: seventy were found dead the next morning.