The Intelligence Service in common with army transport and the sanitary service and every other expert branch has for its object the conserving of the lives of your own soldiers and the taking of those of the enemy, best expressed by an infantry attack on the enemy's trenches, whether to gain a few hundred yards or a belt of eight to ten miles as in the case of the French attack in Champagne in September, 1915, and the German attack on Verdun in February, 1916. The first step is the concentration of batteries for artillery preparation. Gradually, these guns all try out their range with the aeroplanes spotting the fall of their shells. Then, at the scheduled minute they loose their blasts upon the front line trenches which are to be taken. In front of the trenches, of course, are the elaborate barbed-wire entanglements. These are often twenty, thirty or even forty feet deep. There may be more than one series of entanglements and some may be screened in some fashion or other from the effects of artillery fire. Aside from these, _trous de loup_, pits with sharpened sticks to impale the invader, and all the other devices of former times are used--in short, every obstacle from the time of Moses to the modern machine gun. No invader can possibly reach the enemy's trench to contest it with him until these impedimenta are removed. Thousands of short-cut plans and inventions have been offered for cleaning away the barbed wire before an attack, but not one has succeeded because it requires that whoever is to carry out the suggestion or remove the obstruction, must be submitted to murderous grilling machine-gun and rifle fire. Shrapnel shells with their sprays of bullets bursting at a height of a foot above ground remain the approved method of cutting barbed wire. If the barbed wire is not destroyed, the men in the charge are "hung up" in it, as the saying is. Then if a machine gun is still in position in the enemy's trench, they are riddled with bullets where they lie. No form of death could be more pitiless or helpless for the soldier than this. He becomes a target on a spit, as it were. Granted that the barbed wire is swept away perfectly, no charge can succeed if many machine guns or rifles from the trenches are playing upon it. Then men simply rush into a spray of bullets. Therefore, all the teeth must be drawn from the trench itself. This is done by the concentration of high-explosive shells from guns of larger caliber, mostly howitzers, which burst in the earth, tossing up great fountains of dust, burying and smashing the machine guns and driving all the operators into their dugouts, where they are sometimes buried alive.