ABSTRACT
The problems of old age and natural death are hardly yet acknowledged to be within the province of genuine scientific enquiry. The distinction suggesting that natural death might be an epi-phenomenon of life, rather than something of the very nature of the act of living, is shared unequally between August Weismann and Alfred Russell Wallace. Raymond Pearl agreed with Weismann that in some manner or other natural death had evolved, but that it evolved under the auspices of natural selection he irritably denied. The problem of measuring natural selection, which so worried Karl Pearson, is solved: the magnitude of natural selection is measured by the relative increase or decrease in the frequency with which the factor which governs some heritable endowment appears in the population. The shape of the ‘stable age distribution’ is that of a die-away exponential curve, such as one so often meets in the numerical treatment of natural data.
