Beside the staff departments, the Army now consists of 15 regiments of cavalry, 30 batteries of field artillery, 126 companies of coast artillery, and 30 regiments of infantry. These different classes are known as the three arms of the service: Cavalry, artillery, and infantry. Our whole Army to-day numbers 67,259 men. We are the greatest nation, with the smallest army. Our Army, however, is capable of rapid expansion; and, with our National Guard, we need not fear any emergency. This Army, though so small, is in one sense a trained athlete, ready to defend the nation's honor and flag. In another sense, it is a vast practical school, in which the military profession is taught. The students are not only the 60,000 who are now serving, but the many thousands also, who come and go. Men enlist for three years, and although many re-enlist, the Army is constantly receiving recruits, and constantly discharging trained soldiers. These discharged soldiers are often found among our best citizens. The entire corps of over 3,800 officers may be regarded as professors or instructors, whose duty it is to bring the Army up to a state of perfection. To this corps of 3,800 commissioned officers must be added, also, the large number of intelligent non-commissioned officers, who are assistant instructors of the very highest utility. The work of the Army consists of study and practice, instruction and drill. It is an incessant school. There are officers' school, non-commissioned officers' school, school of the soldier, school of the company, school of the battalion, post school,--besides drills and lectures without number. The actual scientific information imparted to the enlisted men is considerable. To specify only in small part: It includes all methods of signaling, up to telegraphy; all methods of preserving and preparing food; all methods of first treatment of wounds; how to estimate distance, to map a country, to care for property and stock, and the most thorough knowledge of weapons and warfare. To become a second lieutenant in the Army, a man must either go through West Point, or have the equivalent of a college education, especially in mathematics, history, and law; and have, besides, an accurate knowledge of what is purely military. And when he is made a second lieutenant and enters upon his career as an officer, his studies begin afresh. He must study to prepare himself for subsequent promotions. Failure in this means dismission. The army officer to-day must be exceedingly thorough and accurate in his knowledge.