We have been assured by our guides in these matters that in the processes of evolution there is no continuous or unbroken chain of progress, that growth or change does not necessarily imply development, but, on the contrary, only as a structure becomes better fitted for its conditions, and only as its organs become more highly specialized for the performance of all the duties involved in its environment, may it be said to be in the line of progress. If this be true, particular attention should be directed to the fact that as secondary sexual characters do not assist their possessor in overcoming the unfavourable conditions of his environment, they are not within the line of true development, but, on the contrary, as their growth requires a great expenditure of vital force, and, as is the case among birds, they often hinder the free use of the legs in running and walking, and entirely destroy the use of the wings for flight, they must be detrimental to the entire structure. For the reason that females have managed to do without them, the plea that the great tusks, horns, teeth, etc., of mammals have been acquired for self-defence, is scarcely tenable. On the subject of the relative expenditure of vital force in the two lines of sexual demarcation, Mr. Darwin remarks: The female has to expend much organic matter in the formation of her ova, whereas the male expends much force in fierce contests with his rivals, in wandering about in search of the female, in exerting his voice, pouring out odoriferous secretions, etc.... In mankind, and even as low down in the organic scale as in the Lepidoptera, the temperature of the body is higher in the male than in the female, accompanied in the case of man by a slower pulse.[21] Yet he concludes: “On the whole the expenditure of matter and force by the two sexes is probably nearly equal, though effected in very different ways and at different rates.”[21] [21] _The Descent of Man_, p. 224. However, as has been observed, the force expended by the male in fierce contests with his rivals, in wandering about in search of the female, and in his exertions to please her when found, does not constitute the only outlay of vitality to which he is subjected; but in addition to all this, there still remains to be considered that force which has been expended in the acquirement of characters which, so far as his own development is concerned, are useless and worse than useless; namely, in birds, combs, wattles, elongated plumes, great wings, etc., and in mammals great horns, tusks, and teeth—appendages which lie outside the line of true development, and, as we have seen, are of no avail except to aid in the processes of reproduction and to assist him in the gratification of his desires; in fact, as these excrescences hinder him in the performance of the ordinary functions of life, they may be regarded in the light of actual hindrances to higher development. CHAPTER III MALE ORGANIC DEFECTS