[Footnote: De Trobriand, Four Years with Potomac Army, p. 64.] In a similar way, though not to the same extent, the other organized and disciplined militia, in both Eastern and Western States, furnished the skeletons of numerous new regiments. The really distinguishing feature in the experience of the regular officers of the line was their life in garrison at their posts, and their active work in guarding the frontier. Here they had become familiar with duty of the limited kind which such posts would afford. This in time became a second nature to them, and to the extent it reached, was, as other men's employments are, their business. They necessarily had to learn pretty thoroughly the army regulations, with the methods and forms of making returns and conducting business with the adjutant-general's office, with the ordnance office, the quartermaster's and subsistence departments, etc. In this ready knowledge of the army organization and its methods their advantage over the new volunteer officers was more marked, as it seemed to me, than in any and all other things. The routine of army business and the routine of drill had to be learned by every army officer. The regular officer of some years' standing already knew, as a matter of course, what a new volunteer officer must spend some time in learning. There is something of value also in the habit of mind formed in actual service, even if the service is in subaltern grades and on a petty scale. Familiarity with danger and with the expectation of danger is acquired, both by the Indian wars of the frontier and by the hunting and field sports which fill more or less of the leisure of garrison life.