development has ceased. If mental growth be unduly forced before structural completion, structural and sexual genesis are retarded or impaired. Professional training in women must, therefore, fall within the child-bearing period. In the case of men of great mental activity there is marked impairment of fertility.[1] The cost of reproduction to males is greatly less than to females, and it therefore follows clearly that the prolonged and intensified mental growth, the result of professional training, is to be deducted in full from the sum of the forces necessary to reproduction. M. Quetelet cannot doubt the influence of professional life upon fertility.[2] Mr. Herbert Spencer says, "that absolute or relative infertility is generally produced in women by mental labor carried to excess, is more clearly shown.... This diminution of reproductive power is not shown only by the greater frequency of absolute sterility, nor is it shown only in the earlier cessation of childbearing, but it is also shown in the very frequent inability of such women to suckle their infants. In its full sense, the reproductive power means the power to bear a well-developed infant, and to supply that infant with the natural food for the natural period."[3]
Even were it not that absolute and relative infertility are against the woman undergoing severe mental discipline having children to inherit her improved cerebral evolution, and in favor of the average or inferior woman, still the very condition of this mental discipline, if the woman is preparing for the professions or skilled labor, involves a postponement of marriage to a period when, in the mass of wives, fecundity has received a permanent check. The average individual wife shows a degree of fecundity which, at the age of twenty-five, diminishes,[4] and this is the period at which the professional woman is prepared to enter upon her business career. The opinion of Mr. Sadler, that delayed marriages developed a degree of fertility in women which compensated for the loss of fecundity consequent upon the delay, is completely overthrown by the tables of Dr. Duncan.[5] If women are to enter the learned professions and skilled labors, they must be devoting themselves to training at a period of their lives when the mass of women are wives—mothers. I think that it must be conceded as a fact that, to contract matrimony during this period of mental and bodily training, would totally defeat the selected life-work of the woman. The desire to become the co-worker with man upon the highest level of man's work belongs only to superior women; if, in addition to this innate superiority, we add that acquired from increased cerebral development, the law of heredity would tend to continually en-
