He who admits the principle of Sexual Selection will be led to the remarkable conclusion that the nervous system not only regulates most of the existing functions of the body, but has indirectly influenced the progressive development of various bodily structures and certain mental qualities. Courage, pugnacity, perseverance, strength and size of body, weapons of all kinds, musical organs, both vocal and instrumental, bright colours, and ornamental appendages have all been indirectly gained by the one sex or the other, through the exertion of choice, the influence of love and jealousy, and the appreciation of the beautiful in sound, colour, or form; and these powers of the mind manifestly depend on the development of the brain.[22] [22] _The Descent of Man_, 1877, p. 617. While the female has been performing the higher functions in the processes of reproduction, through her force of will, or through her power of choice, she has also been the directing and controlling agency in the development of those characters in the male through which, when the human species was reached, he was enabled to attain a limited degree of progress. Since the origin of secondary sexual characters is so clearly manifest, perhaps it will be well for us at this point to examine also their actual significance, that we may be enabled to note the foundation upon which the dogma of male superiority rests. Although the gay colouring of male birds and fishes has usually been regarded as an indication of their superiority over their sombre-coloured mates, later investigations are proving that these pigments represent simply unspecialized material, and an effort of the system to cast out the waste products which have accumulated as a result of excessive ardour in courtship. The same is true of combs, wattles, and other skin excrescences; they show a feverish condition of the skin in the over-excited males, whose temperature is usually much higher than is that of females. We are assured that the skin eruptions of male fishes at the spawning season “seem more pathological than decorative.”[23] In the processes of reproduction, the undeveloped atoms given off from each varying part are reproduced only in the male line. [23] Geddes and Thomson, _The Evolution of Sex_, 1890, p. 24. The beautiful colouring of male birds and fishes, and the various appendages acquired by males throughout the various orders below man, and which, so far as they themselves are concerned, serve no other useful purpose than to aid them in securing the favours of the females, have by the latter been turned to account in the processes of reproduction. The female made the male beautiful that she might endure his caresses.