The explanation which we have given in the preceding chapter of the pairing dresses of the birds can of course be equally well applied to the secondary sexual characters of man. And it holds good also, we believe, with regard to the most primitive _voluntary_ alterations in the appearance of either sex. It is true, indeed, that artificial embellishments or deformations, the work of the individual himself, never can appeal so strongly to the instincts of the other sex as those alterations which are physiologically connected with sexual development. But when, as is the case with most primitive tribes, the so-called means of attraction have remained almost unchanged during innumerable successive generations, one may safely conclude that the instincts of either sex will gradually grow prompt to react with eminent force upon impressions received from such individuals as exhibit these conventional signs of their sex and tribe. Whether the acquired qualities are considered as hereditary, or whether the consistency in the predilections of all the members of the same tribe be explained—in the Weissmannian or the neo-Darwinian way—as a result of selection, there will always be found in either sex a sort of constitutional liking for certain fixed qualities in the appearance of the opposite sex. An appearance and a behaviour which, in the ancestors of an individual, male or female, have stirred the instinctive life of the opposite sex through generations past by, must needs improve his or her chances in courtship. The more a suitor approaches the ideal which unconsciously, and one may say physiologically, is embodied in the inherited impulses of every female, the more helplessly is she exposed to the fascination of his charms. And when, at a certain higher state of development, the males begin to practise a selection between rival females, they will undoubtedly be influenced in their choice by the same sort of inherited predilections. And there is no reason why these predilections should be restricted to anatomical qualities—why artificial adornments, perhaps even detached gems, which have only been traditional during some generations, should not influence sexual preferences in the same direct way—that is, without any intervention of an æsthetic judgment, as secondary sexual characters proper influence them. This circumstance justifies us in treating the outward physical appearance and the conventional means of embellishing it in conjunction with each other. An outward sign, whether natural or artificial, which has often enough been connected with the impression of the other sex will necessarily tend to awaken sexual feelings.