If it is desired to waterproof shoes at any time, a considerable amount of neat's-foot oil should be rubbed into the leather. Waterproof leather causes the feet of some men to perspire unduly and keeps them constantly soft. Light woolen or heavy woolen socks will habitually be worn for marching. Cotton socks will not be worn unless specifically ordered by the surgeon. The socks will be large enough to permit free movement of the toes, but not so loose as to permit of wrinkling. Darned socks, or socks with holes in them, will not be worn in marching. Until the feet have hardened they should be dusted with foot powder, which can be obtained at the regimental infirmary, before each day's march. Clean socks should be worn daily. As soon as possible after reaching camp after a day of marching the feet should be washed with soap and water, and the soldier should put on a dry pair of socks and his extra pair of shoes from his surplus kit. If the skin is tender, or the feet perspire, wash with warm salt water or alum water, but do not soak the feet a long time, as this, although very comforting at the time, tends to keep them soft. Should blisters appear on the feet, prick and evacuate them by pricking at the lower edge with a pin which has been passed through the flame of a match and cover them with zinc oxide plaster applied hot. This plaster can be obtained on request at the regimental infirmary. If serious abrasions appear on the feet, or corns, bunions, and ingrowing nails cause trouble, have your name placed on sick report and apply to the surgeon for treatment. Cut the toenails square (fairly close in the middle, but leaving the sides somewhat longer), as this prevents ingrowing nails. CHAPTER V. EXTRACTS FROM CAVALRY DRILL REGULATIONS. UNITED STATES ARMY, 1916. =Section 1. Definitions.= =Alignment.=--The placing of several troopers or units on the same straight line; also the line on which such adjustment is made. =Assembly.=--The grouping =in order=, and in a close-order formation, of the elements of a command. The special arrangement and condition that constitute =order= for each unit are explained in the corresponding part of the text. The purpose of the assembly is to bring about a close-order formation in order. =Base.=--The element on which a formation or movement is regulated. The base may be a trooper, two, four, section, platoon, or larger unit. When the base is a single trooper in ranks, he may also be termed the =guide=. =Center.=--The middle point or element of a command. If the number of elements considered be even, the right center element will be meant when the center element is referred to.