As reproductive activity dies down, social conditions become more stable, a comparatively balanced state of adjustment tends to be established, insanitary surroundings can be bettered, disease diminished, and the death-rate lowered.
How much may thus be accomplished we realize when we compare the admirably precise and balanced pages in which Charles Booth, in the concluding volumes of his great work, has summarized his survey of London, with the picture presented by Chadwick and Gavin half a century earlier.
Ugly and painful as are many of the features of this modern London, the vision which is, on the whole, evoked is that of a community which has attained self-consciousness, which is growing into some faint degree of harmony with its environment, and is seeking to gain the full amount of the satisfaction which an organized urban life can yield.
Booth, who appears to have realized the significance of a decreased fertility in the attainment of this progress, hopes for a still greater fall in the birth-rate; and those who seek to restore the birth-rate of half a century ago are engaged on a task which would be criminal if it were not based on ignorance, and which is, in any case, fatuous.
The whole course of zoological evolution reveals a constantly diminishing reproductive activity and a constantly increasing expenditure of care on the offspring thus diminished in number.2 Fish spawn their ova by the million, and it is a happy chance if they become fertilized, a highly unlikely chance that more than a very small proportion will ever attain maturity. Among the mammals, however, the female may produce but half a dozen or fewer offspring at a time, but she