The interior defense should be organized about the houses most strongly built and least visible to the enemy's artillery. It should include hidden communications between these strong points, thus facilitating a prolonged defense. 214.--Special precautions. The streets should be barricaded and loopholes provided in the walls of the houses. Precautions should be taken against fire: pails of water, boxes of sand provided in the houses. DEFENSE OF A DEFILE. 215.--To keep the exits open for an advance. If the aim is to keep the exits open so as to permit the advance of troops, the defense should be organized at some distance in front of the defile: far enough to permit the unimpeded progress of the advance. 216.--To keep exits open for a retreat. If the aim is to keep the exits open so as to cover the retreat of troops, the roads at the bottom of the defile should be left free and the defense troops so placed as to draw the enemy's fire on other points. 217.--To block the defile. If the aim is to block the defile, the defense should be organized in the interior of the defile on both sides of the place of greatest width, so as to secure convergence of fire. Echelon detachments all along the defile to act as a rear guard in case a retreat is necessary. Keep the flanks well protected. NIGHT DEFENSE OF A POSITION 218.--Precautions against attack. Attack should be guarded against by accumulating obstacles and the defense further prepared by previous reconnoitering of the best ground for counter-attacks. 219.--Receive with violent fire and immediate counterattacks. The enemy's charge should be met with a violent fire at the shortest possible range, followed immediately by counter-attacks with the bayonet, especially on the flanks. THE COUNTER ATTACK. 220.--Confine to definite Objective. Indicate the objective very definitely including the position to be reached but not gone beyond. Its direction should not interfere with the fire of neighboring troops. 221.--Necessary Reconnaissance. The Counter Attack should be prepared cautiously and the itinerary carefully, even if rapidly, reconnoitered. (This may have been done as part of the preparation of the defense. It should be done with special care if the counter-attack is to take place at night.) 222.--Watch for opportunity. It may be decided upon independently of the incidents of the defense or to take advantage of the mistakes or weakness of the adversary. 223.--Counter from short distance. The most favorable moment is when the enemy is within a short distance and its artillery consequently obliged to stop or to lengthen its fire. 224.--Sudden and intense fire. It should be launched suddenly so as to surprise the enemy and pushed vigorously, the fire being increased to great intensity along the whole front. 225.--Rapid and continuous advance. Rapidity and continuity of advance is essential. 226.--Bayonet charge.