This reference originally appeared at Wikipedia circa 2013, but may have been removed. I have linked to the original Wikipedia reference using archive.org, and I've also listed additional references:

I contend that we are the finest race in the world and that the more of the world we inhabit the better it is for the human race. Just fancy those parts that are at present inhabited by the most despicable specimens of human beings what an alteration there would be if they were brought under Anglo-Saxon influence...

https://web.archive.org/web/20140821160610/https://en.wikipedia.org/wiki/Cecil_Rhodes

Additional Sources:

Africa and The West A Documentary History (2nd Edition) Vol 1: From The Slave Trade to Conquest, by William H. Worger, Nancy L. Clark, Edward A. Alpers (page 221)

Confession of Faith, University of Oregon page

More Sources (Google Books Search)

Another reference updated to Archive.org: Cecil Rhodes, by John E. Flint:
The original links to the John E. Flint reference are:
1) http://users.clas.ufl.edu/harlandj/courses/4264/documents_British_empire.pdf
2) https://www.palgrave.com/us/book/9780333778852#reviews

Both links now forward to an unrelated page. Here is the archived link to the PDF:
1) Cecil Rhodes