As an alternative explanation, he would advance no new theory, but simply apply the known laws of evolution. He points out, and dwells upon, the high importance of protection to the female while sitting on the nest. In this way he accounts for the more sombre hues of the female; and finds strong support in the fact that in those birds in which the male undertakes the household duties, he is of a domestic dun colour, and his gad-about-spouse is bedizened like a country-girl at fair time. With regard to the brilliant hues themselves, he draws attention to the fact that depth and intensity of colour are a sign of vigour and health--that the pairing time is one of intense excitement, and that we should naturally expect to find the brightest hues then displayed. Moreover, he shows--and this is most important to us--that "the most highly-coloured and most richly varied markings occur on those parts which have undergone the greatest modification, or have acquired the most abnormal development."[2] It is not our object to discuss these rival views; but they are here laid down in skeleton, that the nature of the problem of the principles of colouration may be easily understood. Seeing, then, how infinitely varied is colouration, and how potently selection has modified it, the question may be asked, "Is it possible to find any general system or law which has determined the main plan of decoration, any system which underlies natural selection, and through which it works"? We venture to think there is; and the object of this work is to develop the laws we have arrived at after several years of study. [Illustration] [1] Wallace, Tropical Nature, p. 206. [2] _Op. cit._, p. 206. CHAPTER II. INHERITED MEMORY. Many of our observations seemed to suggest a quasi-intelligent action on the part of the beings under examination; and we were led, early in the course of our studies, to adopt provisionally the hypothesis that memory was inherited--that the whole was consequently wiser than its parts, the species wiser than the individual, the genus wiser than the species. One illustration will suffice to show the possibility of memory being inherited. Chickens, as a rule, are hatched with a full knowledge of how to pick up a living, only a few stupid ones having to be taught by the mother the process of pecking. When eggs are hatched artificially, ignorant as well as learned chicks are produced, and the less intelligent, having no hen instructor, would infallibly die in the midst of plenty. But if a tapping noise, like pecking, be made near them, they hesitate awhile, and then take to their food with avidity. Here the tapping noise seems certainly to have awakened the ancestral memory which lay dormant.