Here, then, in the female bird we see developed in a remarkable degree the power of discrimination, the exercise of taste, a sense of beauty, and the ability to choose—qualities which the facts brought forward by scientists show conclusively to have been acquired by the female and by her transmitted to her offspring. Regarding males, outside the instinct for self-preservation, which, by the way, is often overshadowed by their great sexual eagerness, no distinguishing characters have been acquired and transmitted, other than those which have been the result of passion, namely, pugnacity and perseverance. This excessive eagerness which prompts them to parade their charms whenever such display is likely to aid them in the gratification of their desires is developed only in the male line. According to the law of heredity, those modifications of the male which have been the result of Sexual Selection appear only in the sex in which they originated. It will be well for us to remember that according to Mr. Darwin’s theory of pangenesis, sexes do not differ much in constitution before the power of reproduction is reached, but that after this time the undeveloped atoms or gemmules which are cast off from each varying part in the one sex would be much more likely to possess the proper affinities for uniting with the tissues of the same sex, and thus becoming developed, than with those of the opposite sex.[18] [18] _The Descent of Man_, 1877, p. 232. We are given to understand that secondary sexual characters are extremely variable, also that variability denotes low organization; secondary sexual characters indicate that the various organs of the structure have not become specialized for the performance of their legitimate functions. Highly specialized forms are not variable. To sum up the argument thus far: It has been observed that through the separation of the sexes, and the consequent division of labour, there have been established two diverging lines of development. While the male pheasant has been inheriting from his male progenitors fantastic ball-and-socket ornaments, and huge wings which are utterly useless for their legitimate purpose, the female, in the meantime, has been receiving as her inheritance only those peculiarities of structure which tend toward uninterrupted development. Within her have been stored or conserved all the gain which has been effected through Natural Selection, and as a result of greater specialization of parts, there have been developed certain peculiarities in her brain nerve-cells, by which she is enabled to exercise functions requiring a considerable degree of intelligence.