Then follows the chequered period of the prime of life and middle age, during which the liability of men to industrial accidents, war and other causes of special mortality, irrespective of their greater inclination to emigrate, is generally sufficient to outweigh the dangers of childbirth or premature decay among the women, who tend, accordingly, to predominate in number at this stage.
It is remarkable that the same tendency for the proportion of the young to fall off is perceptible in new countries as well as in the older civilizations, setting aside the influence of immigration at the prime of life in depressing the proportion of children.
In France, on the contrary, the low natality having been so long continued, has raised the death-rate, by reason of the balance of proportion having been shifted by it from youth and the prime of life to old age.
The disease struck people in childhood or in the prime of life.