Only a few researchers had an inkling that psychology was an important new means of understanding combat. Before the turn of the century, articl»s in obscure medical journals in St. Petersburg and Moscow discussed what was called hysteria in soldiers on campaign. From the Sino-Japanese Naval War of 1894-95 came medical reports of “traumatic delirium” among Japanese troops who had been “wounded in the neighborhood of the places where enormous shells had exploded.” Toward the end of 1900 Morgan Finucane, a British army contract surgeon at Aldershot, treating soldiers evacuated from the Boer War, speculated in a Lancet article that artillery fire might be responsible for the mental disorientation he found in some of his patients. And an American army medical officer, Capt. R. L. Richards, observing combat during the Russo-Japanese War, reported hospital wards and evacuation trains from the front filled with troops, physically untouched, who were mentally impaired and no longer any good for soldiering. None of these reports seem to have made the least impression upon either medical or military thought. The notion that normal men could be mentally as well as physically wounded by the stresses of modern combat could not, as yet, challenge society’s long and dearly held misconceptions about what it was really like to be trapped inside a battle.

And then came August 1914. Playing the general too much, some writers have characterized the opening stages of the Great War as a period of free maneuver, and indeed, from the strategic to the tactical levels, the combatant armies did contend with one another in ways that corresponded to the fondest imaginings of any staff-college student contemplating paper victories. But this war was not the lark many anticipated. By the time the maneuvering was definitively finished in December 1914, the French Army alone had suffered more than 350,000 casualties, and on other parts of the front the numbers were sufficient to crush even the sturdiest optimism, save, of course, that of the high commands.

Apart from the vast numbers of troops engaged, the most immediately noticeable feature of this new war was the antagonists’ relentlessly industrial delivery of fire upon their enemies. And as time passed, their skill at deploying stupendous, unprecedented quantities of shell improved by quantum leaps. Less than a year after the war began, more artillery shells were fired at the Battle of Neuve-Chapelle than had been fired in all of the Boer War.

The sheer magnitude of this shellfire early on produced rumors that men died from that effect alone. The Times History of the War reports that as early as the Battle of the Marne, “dead men had been found standing in the trenches . . . [and] every normal attitude of life was imitated by these dead men” who had no signs of physical injury. Observers lucky enough to retain their wits thought it inconceivable that men could live through such experiences unaffected.

Soon enough, all the warring nations began to receive soldiers evacuated from the front who had become mentally disabled. In Germany the psychologist Karl Birnbaum drew a clinical picture from the first six months of the war in which nervous conditions arose from the fatigue and exhaustion of fighting that included “great weariness and profuse weeping, even in otherwise strong men.” One of Birnbaum’s colleagues reported soldiers who had lost their voices, who were unable to walk steadily, who were easily startled, and who had difficulty controlling their emotions.

An American psychiatrist, Clarence A. Neymann, who served with the German Red Cross in Heidelberg from the earliest days of the war, saw no cases at all until after the Battle of the Marne had halted the initial German Army offensive. Then, Neymann recognized, “Hardly a transport of sick and wounded . . . did not contain its quota of mental cases.” At first such cases were regarded as nuisances by hard-pressed surgeons and were sent farther to the rear, where after a period of “stagnation” they were returned to the front lines. One immediately noticeable class of mental case, marked by tremors, difficulty in standing, and chronic indigestion, quickly acquired the informal diagnosis of Granatfieber , or grenade fever. To these were added a growing number of casualties who had suffered “especially trying experiences” at the front. Soon, Neymann reported, his wards became so crowded that the overflow of patients had to be shunted to base hospitals for warehousing.