We are ignorant of the laws of variety-production; but we see it going on as a principle in nature, and it is obviously favorable to the supposition … - Robert Chambers

The whole train of animated beings, from the simplest and oldest up to the highest and most recent, are, then, to be regarded as a series of advances of the principle of development, which have depended upon external physical circumstances, to which the resulting animals are appropriate.

Of late years... it has been successfully shewn that the human race might have had one origin, for anything that can be inferred from external peculiarities.

It appears from this inquiry that color and other physiological characters are of a more superficial and accidental nature than was at one time supposed.