the largest individual force maintains those more active adjustments, "simultaneous and successive," between the internal and external, which indicate the most vigorous life. We must look, then, to something more than a direct antagonism, between growth and reproduction, to account for unlikenesses of the sexes in plant or animal. "The minutest organisms multiply asexually in their millions;" but "those which do not multiply asexually at all are a billion or a million times the size of those which thus multiply with the greatest rapidity;" yet these comparative rates of growth and multiplication can offer no key to any of the problems of evolution.
Mr. Spencer reasons that birds, as a class, are less in size than mammals, because they habitually expend more muscular energy in flight; and that lions, having a digestive system not superior to men, yet attain to a larger size and are more prolific, because they have a less active nervous system to sustain. Then, if women normally have equal appropriative powers with men, the surplus nutriment not needed for their smaller physiques may be constitutionally handed over to reproduction. Natural selection has originated an admirably complete system of related provisions to this distinct end. This fact must lead us to the conclusion that the aggregate of feminine force is the full and fair equivalent of all masculine force, physical or psychical.
The maternal constitution elaborates nutriment, from which it is itself to receive no direct benefit. But, do we forget the inexorable conditions which compel the human father to expend equivalent muscular or mental force to feed, not himself, but his dependents? Whenever man does not interfere, monogamy seems to be the general order of Nature with all higher organisms. Where the cost of obtaining food is great, the parents sustain commensurate burdens in rearing their young; and, with these claims, I think it will be found that monogamy is the primal condition of reproduction. The warlike duty of defense is also borne chiefly by males, and must often be an immense tax on the energies.
Among the beings of a lower type, plant and animal, all the more recent observations indicate that Nature herself systematically favors the females––the mothers of the destined races. Nature's sturdiest buds and her best-fed butterflies belong to this sex; her female spiders are large enough to eat up a score of her little males; some of her mother-fishes might parody the nursery-song, "I have a little husband no bigger than my thumb." Natural selection, whether the working out of intelligent design or otherwise, would make this result inevitable. We might expect that the neuter bee could be nourished into the queen-mother. If required to judge a priori, we should decide, if there is no predetermination of sex, that the best-fed embryos would most readily become female; since the one special fact in the feminine organism is the innate tendency to manufacture, and, within certain limits, to store up reserved force for the future needs of offspring.
