“The duties of a soldier are very unequally divided in regard to time. Some days he may have nothing whatever to do but to pass the time as best he can; and then of a sudden he may be called upon to perform all that his physical powers can possibly accomplish, and often his power of endurance yields to exhaustion, and he is obliged to stop ere his task is completed. These extremes of physical exertion may not accord with the strictest rules of physiology, but they certainly do not conflict with the rules of military life.” – Wilbur Fisk, Hard Marching Every Day (eds. E. and R. Rosenblatt)