With savages, the weak in body or mind are soon eliminated. We civilized men, on the other hand, do our utmost to check the process of elimination. We build asylums for the imbecile, the maimed and the sick. Thus the weak members of civilized societies propagate their kind. No one who has attended to the breeding of domestic animals will doubt that this must be highly injurious to the race of man. Hardly anyone is so ignorant as to allow his worst animals to breed.

The willing horse is always overworked.

If man had not been his own classifier, he would never have thought of founding a separate order for his own reception.

Freedom of thought is best promoted by the gradual illumination of men’s minds which follows from the advance of science.

The age-old and noble thought of 'I will lay down my life to save another,' is nothing more than cowardice.

The young blush much more freely than the old but not during infancy, which is remarkable, as we know that infants at a very early age redden from passion.

Seeing every height crowned with its crater, and the boundaries of most of the lava-streams still distinct, we are led to believe that within a period, geologically recent, the unbroken ocean was here spread out. Hence, both in space and time, we seem to be brought somewhat near to that great fact — that mystery of mysteries — the first appearance of new beings on this earth.