Related to this is the surgery of wounds arising in military service, which concerns the extraction of missiles. In city practice experience of these is but little, for very rarely even in a whole lifetime are there civil or military combats. In fact such things occur most frequently and continuously in armies abroad. Thus, the person intending to practice this kind of surgery must serve in the army, and accompany it on expeditions abroad; for in this way he would become experienced in this practice.

Hippocrates - The Physician 14, as translated by Paul Potter, Loeb Classical Library, Hippocrates Volume VIII.