"The machines came right on, ignoring the hospital with the German wounded, indicating they had full knowledge of their objective, until they were over a wing of the Red Cross hospital that contained the operating room on the ground floor. In the operating room a man was on the table for a most difficult surgical feat. Around him were gathered the staff of the hospital and its brilliant surgeons. Lieutenant Sage of New York had just given him the anesthetic when one of the airplanes let the bomb drop. It was a big fellow. It must have been all of 250 pounds of high explosive. "It hurtled downward, carrying the two floors before it. Through the gap thus made wounded men, the beds in which they lay, convalescents, and all on the floors came crashing down to the ground. The bomb's force extended itself to wreck the operating room, where the man on the table, Lieutenant Sage, and all in the room were killed. In all there were thirty-seven lives lost, including three Red Cross nurses. "The building caught fire. The concussion had blown the stairs down, so that escape from the upper floors seemed impossible. But the convalescents and the soldiers, who had run to the scene of the bombing, let the very ill ones out of the windows, and escape was made in that way. "And then, to cap the climax, the German airplanes returned over the spot of their ghastly triumph and fired on the rescuers with machine guns. God will never forgive the Huns for that act alone. Nor will our comrades ever forget it." The statement of Colonel Andrews was corroborated by a number of other officers. To protect artillery against counter-fire of all kinds, both sides from the beginning used the art of camouflage. This was resorted to particularly against scouting airplanes. At first the branches of trees and similar natural cover were used to deceive the airmen. Later the guns themselves were painted with protective colorations, and screens of burlap were used instead of branches. The camoufleur, as the camouflage artist was called, speedily extended his activities to screens over highways, preventing airmen from seeing troops in motion, to the protective coloration of lookout posts, and of other necessary factors along the fighting front. Camouflage also found great usefulness in the protective coloration of battleships and merchant vessels. Scientific study went hand in hand with the art, the object being to confuse the enemy and to offer targets as small as possible to the enemy gunners.