If a single cell, under appropriate conditions, becomes a man in the space of a few years, there can surely be no difficulty in understanding how, under appropriate conditions, a cell may, in the course of untold millions of years, give origin to the human race.1
Principles of Biology.
Note 1. Tennyson: Maud. As nine months go to the shaping an infant ripe for his birth, So many a million of ages have gone to the making of man. [back]