Just read Tarzan the Untamed
. The seventh Tarzan book and sixth novel.
What a rambling mess this was, story wanders all over the place with very little coherence.
And Burroughs really turns up the racism with this one, too. He even goes so far as to create a "race" of people to be racist against.
In the earlier books the racism seemed to stem more from ignorance, but this book is aggressively racist.
I can only guess that he was really buying into Eugenics, which was near the height of it's popularity in America when he wrote this.
The book does have some good scenes and some interesting stuff on Tarzan's duality as English Nobleman and
Savage Ape-Man, but it's a mess as a whole.