appreciable effect, and therefore, other than social forces must be appealed to for its explanation. Sociological statisticians in approaching this question have often assumed that normally the higher birth rate of males is exactly balanced by their higher death rate, and that thus the divine power, the natural law, or the biological forces at work, tend to establish an equality either in the total numbers of males and females, or in the numbers of adults. Under such an assumption any deviation from equality would be explained by appealing to the agency of disturbing social forces of which the most obvious and most constantly invoked are migration and war. The present drift of biological speculation, however, seems to be away from this view and towards the position that in no species of plant or animal is there any tendency towards exactly equal numbers of the two sexes, but that the normal proportion is determined for each species by what is most to its advantage in the fight for life and that the numbers fluctuate about that proportion under the influence of various disturbing forces.[1] Partly, it may be, in consequence of this drift of opinion the question of the numerical proportion of the sexes in the human species has been recently reopened and an effort made to prove that the deviations from equality in the numbers of the sexes at any place and time are due primarily to biological forces controlling the births and deaths, and only in a subordinate degree to such social forces as migration and war.[2]
From this point of view the facts regarding the proportions of the sexes in the United States, will be examined in the following paper. At the threshold of such an examination, a serious difficulty meets the inquirer. In this country the records of births and deaths are so fragmentary and imperfect, that little aid can be derived from them, and none at all for the country as a whole. Hence, such records, although of primary importance in an investigation of this character, will be passed over with slight attention and the study based upon the census figures. Such a
