You can download it right here. In the preface, Hunter thanks his buddy Herbert E. Walter for his help. Herbert was a famous evolutionary biologist, a member of the American Eugenics Society, and a rabid eugenist. Herbert wrote a nasty essay called Human Conservation. You can read some of it here. Horatio Newman, a Scopes trial witness, was also a member of the American Eugenics Society.
Thanks for all the great information about Hunter and his friends.