625. With new or untrained troops, the process of hardening the men to this work must be gradual. Immediately after being mustered into the service the physical exercises and marching should be begun. Ten-minute periods of vigorous setting-up exercises should be given three times a day to loosen and develop the muscles. One march should be made each day, with full equipment, beginning with a distance of 2 or 3 miles and increasing the distance daily as the troops become hardened, until a full day's march under full equipment may be made without exhaustion. 626. A long march should not be made with untrained troops. If a long distance must be covered in a few days, the first march should be short, the length being increased each succeeding day. 627. Special attention should be paid to the fitting of shoes and the care of feet. Shoes should not be too wide or too short. Sores and blisters on the feet should be promptly dressed during halts. At the end of the march feet should be bathed and dressed; the socks and, if practicable, the shoes should be changed. 628. The drinking of water on the march should be avoided. The thirst should be thoroughly quenched before starting on the march and after arrival in camp. On the march the use of water should, in general, be confined to gargling the mouth and throat or to an occasional small drink at most. 629. Except for urgent reasons, marches should not begin before an hour after daylight, but if the distance to be covered necessitates either breaking camp before daylight or making camp after dark, it is better to do the former. Night marching should be avoided when possible. 630. A halt of 15 minutes should be made after the first half or three-quarters of an hour of marching; thereafter a halt of 10 minutes is made in each hour. The number and length of halts may be varied, according to the weather, the condition of the roads, and the equipment carried by the men. When the day's march is long a halt of an hour should be made at noon and the men allowed to eat. 631. The rate of march is regulated by the commander of the leading company of each regiment, or, if the battalions be separated by greater than normal distances, by the commander of the leading company of each battalion. He should maintain a uniform rate, uninfluenced by the movements of troops or mounted men in front of him. The position of companies in the battalion and of battalions in the regiment is ordinarily changed daily so that each in turn leads. 632. The marching efficiency of an organization is judged by the amount of straggling and elongation and the condition of the men at the end of the march. An officer of each company marches in its rear to prevent undue elongation and straggling.