=6.= The various elements of an interior guard classified according to their particular purposes and the manner in which they perform their duties are as follows: (_a_) The main guard. (_b_) Special guards: Stable guards, park guards, prisoner guards, herd guards, train guards, boat guards, watchmen, etc. =Section 3. Details and rosters.= =7.= At every military post, and in every regiment or separate command in the field, an interior guard will be detailed and duly mounted. It will consist of such number of officers and enlisted men as the commanding officer may deem necessary, and will be commanded by the senior officer or noncommissioned officer therewith, under the supervision of the officer of the day or other officer detailed by the commanding officer. =8.= The system of sentinels on fixed posts is of value in discipline and training because of the direct individual responsibility which is imposed and required to be discharged in a definite and precise manner. While the desirability of this type of duty is recognized, it should only be put in practice to an extent sufficient to insure thorough instruction in this method of performing guard duty, and should not be the routine method of its performance. The usual guard duty will be performed by watchmen, patrols, or such method as in the opinion of the commanding officer may best secure results under the particular local conditions. =9.= At posts where there are less than three companies the main guard and special guards may all be furnished by one company or by details from each company. It is directed that whenever possible such guards shall be furnished by a single company, for the reason that if guard details are taken from each organization at a post of two companies, troops, or batteries it will result in both being so reduced as to seriously interfere with drill and instruction, whereas if details are taken from only one the other is available for instruction at full strength. Where there are three or more companies, the main guard will, if practicable, be furnished by a single company, and, as far as practicable, the same organization will supply all details for that day for special guard, overseer, and fatigue duty. In this case the officer of the day and the officers of the guard, if there are any, will, if practicable, be from the company furnishing the guard. =10.= At a post or camp where the headquarters of more than one regiment are stationed, or in the case of a small brigade in the field, if but one guard be necessary for the whole command, the details will be made from the headquarters of the command. If formal guard mounting is to be held, the adjutant, sergeant major, and band to attend guard mounting will be designated by the commanding officer. =11.= When a single organization furnishes the guard, a roster of organizations will be kept by the sergeant major under the supervision of the adjutant. (See Appendix B.)