The probability may now be assumed that the human race sprung from one stock which was at first in a state of simplicity if not barbarism. - Robert Chambers

I suggest, then... that the first step was an advance under favor of peculiar conditions, from the simplest forms of being, to the next more complicated, and this through the medium of the ordinary process of generation.

It must be borne in mind that the gestation of a single organism is the work of but a few days, weeks, or months, but the gestation (so to speak) of a whole creation is a matter probably involving enormous spaces of time.

The elder Herschel, directing his wonderful tube towards the sides of our system, where stars are planted most rarely... was enabled with awe struck mind to see suspended in the vast empyrean astral systems, or, as he called them, firmaments, resembling our own. Like light cloudlets to a certain power of the telescope, they resolved themselves, under a greater power, into stars, though these generally seemed no larger than the finest particles of diamond dust. The general forms of these systems are various; but one at least has been detected as bearing a striking resemblance to the supposed form of our own. The distances are also various... The farthest observed by the astronomer were estimated by him as thirty-five thousand times more remote than Sirius, supposing its distance to be about twenty thousand millions of miles. It would thus appear, that not only does gravitation keep our earth in its place in the solar system, and the solar system in its place in our astral system, but it also may be presumed to have the mightier duty of preserving a local arrangement between that astral system and an immensity of others, through which the imagination is left to wander on and on without limit or stay, save that which is given by its inability to grasp the unbounded.