Transcriber's Note
A few obvious printer errors were repaired, but otherwise spelling and punctuation were retained as in the original, including variant spellings on the same words (for example: "color" and "colour").
The index is not listed in the original Contents page.
In the original, index entries for "Humanity, degrees of," and "Species, power to improve the," erroneously referred to page 1. These entries have been corrected to page 3.