Adequately to deal with this difficulty would involve examining in detail the actual mental attitude of the adult towards the young, especially in regard to matters directly or indirectly touching upon interests of sex. The subject is a difficult one, and if we limit ourselves to the purely human standpoint, ugly and depressing. The biologist, however, need not confine himself to so cramped an outlook, and by means of collecting his observations over a much larger field is able to some extent to escape the distorting effects of natural human prejudice. Viewed in a broad way, it is neither surprising nor portentous that there should naturally exist a strong and persistent jealousy between the adult and the young. Indeed, many of the superficial consequences of this fact are mere commonplaces. Throughout most of the lower animals the relation is obvious and frankly manifested. Indeed, it may be regarded as a more or less inevitable consequence of any form of social life among animals. As such, therefore, it may be expected to appear in some form or other in the human mind. The manifestations of it, however, will by no means necessarily take easily recognizable forms. The social pressure to which the mind is subject will tend to exclude such a feeling from at any rate full consciousness, and such manifestations as are allowed it will be in disguised and distorted forms. It seems difficult to avoid the conclusion that some dim and unrealized offshoot of such a jealousy {85} between adult and young is responsible for the unanimity with which man combines to suppress and delay the development of any evidence of sexual interest by the young. The intensity of the dislike which is felt for admitting the young to share any part of the knowledge of the adult about the physiology of sex is well illustrated by the difficulty parents feel in communicating to their children some of the elementary facts which they may feel very strongly it is their duty to impart. A parent may find himself under these circumstances trying to quiet his conscience with all sorts of excuses and subterfuges while he postpones making the explanations which duty and affection urge upon him as necessary for the health and happiness of his child. An unwillingness so strong and irrational as this must have its root in subconscious processes charged with strong feeling. The tendency to guard children from sexual knowledge and experience seems to be truly universal in civilized man and to surpass all differences of morals, discipline, or taste. Amongst primitive savages the principle has not acquired the altruistic signification which civilized man has given it, but operates as a definite exclusion to be overcome only by solemn ceremonies of initiation and at the price of submission to painful and sometimes mutilating rites.