Let me briefly indicate how the different duties may be made to fall into line according to the plan of classification which has just been suggested. The whole field of duty may be divided into three main provinces:[5] those duties which relate to ourselves, those which we owe to all men, and those which arise in the special relations of the family, the state, etc.: I. The Self-regarding Duties. These may again be subdivided into duties relating to our physical nature, to the intellect, and to the feelings. Under the head of physical duties belong the prohibition of suicide, and the duties of physical culture, temperance, and chastity. Intellectual Duties.--Under this head may be ranged the duty of acquiring knowledge and the subsidiary duties of order, diligence, perseverance in study; while, for those who are beyond the school age, special stress should be laid on the duty of mental genuineness. This may be expressed in the words: To thine own mental self be true. Study thine own mental bent. Try to discover in what direction thy proper talent lies, and make the most of it. Work thine own mine: if it be a gold-mine, bring forth gold; if it be a silver-mine, bring forth silver; if it be an iron-mine, bring forth iron. Endeavor to master some one branch of knowledge thoroughly well. It is for thee the key which opens the gates of all knowledge. The need of general culture is felt by all, but the concentration of intellectual efforts on special studies is not inconsistent with it. On the contrary, special studies alone enable us to gain a foothold in the realm of knowledge. A branch of knowledge which we have mastered, however small, may be compared to a strong fortress in an enemy's country, from which we can sally forth at will to conquer the surrounding territory. Knowledge may also be likened to a sphere. From every point of the circumference we can, by persistent labor, dig down to the center. He who has reached the center commands the sphere. Duties which relate to the Feelings.--The principal duty under this head may be expressed in the twofold command--control and purify thy feelings! The feelings which need to be repressed are anger, fear, self-complacency. Let the teacher, when he reaches this point, dwell upon the causes and the consequences of anger. Let him speak of certain helps which have been found useful for the suppression of angry passion. Let him distinguish anger from moral indignation. In dealing with fear let him pursue the same method. Let him distinguish physical from moral cowardice, brute courage from moral courage, courage from fortitude.