The amount of strain that can be actually borne with impunity by any individual is no doubt dependent upon a considerable number of complex conditions. Recent research has shown that among the _psychological_ conditions one of quite special importance is constituted by the general state of integration of the motive forces of the mind. A person whose instincts and impulses are co-ordinated sufficiently to maintain, as regards all the leading aspects of life, a relatively harmonious functioning of the whole personality, can preserve mental health in circumstances under which a less integrated mind would fail, owing to the waste of energy occasioned by the internal struggles of the conflicting tendencies and emotions aroused in situations of difficulty or danger. The attainment of the desirable degree of mental integration is itself very largely dependent upon a process of successful mental growth and development, in the course of which the conflicting tendencies and motives (of which the mind is so largely made up) so modify and mould each other as to permit of the proper discharge of psychical energy along all suitable channels without undue friction or inhibition. Great importance attaches, therefore, from the point of view of mental efficiency and stability in adult life, to the influences which control the development of the conative trends during childhood and adolescence. [Sidenote: Family influences] It is to the consideration of one of the most potent of these influences that the present pages are devoted. Even on a superficial view it is fairly obvious that, under existing social conditions the psychological atmosphere of the home life with the complex emotions and sentiments aroused by, and dependent on, the various family relationships must exercise a very considerable effect on human character and development. Recent advances in the study of human conduct indicate that this effect is even greater than has been generally supposed: it would seem that, in adopting his attitude towards the members of his family circle, a child is at the same time determining to a large extent some of the principal aspects of his relations to his fellow men in general; and that an individual's outlook and point of view in dealing with many of the most important questions of human existence can be expressed in terms of the position he has taken up with regard to the problems and difficulties arising within the relatively narrow world of the family. [Sidenote: their importance, difficulty, and complexity]