If such a construction is to be given to the act of 1821 as to confine the transfer of officers from the old to the new establishment to the _corps of troops_--that is, to the line of the Army--the whole staff of the Army in every branch would not only be excluded from any appointment in the new establishment, but altogether disbanded from the service. It would follow also that all the offices of the staff under the new arrangement must be filled by officers belonging to the new establishment after its organization and their arrangement in it. Other consequences not less serious would follow. If the right of the President to fill these original vacancies by the selection of officers from any branch of the whole military establishment was denied, he would be compelled to place in them officers of the same grade whose corps had been reduced, and they with them. The effect, therefore, of the law as to those appointments would be to legislate into office men who had been already legislated out of office, taking from the President all agency in their appointment. Such a construction would not only be subversive of the obvious principles of the Constitution, but utterly inconsistent with the spirit of the law itself, since it would provide offices for a particular grade, and fix every member of that grade in those offices, at a time when every other grade was reduced, and among them generals and other officers of the highest merit. It would also defeat every object of selection, since colonels of infantry would be placed at the head of regiments of artillery, a service in which they might have had no experience, and for which they might in consequence be unqualified.