He reasoned that black Africans were very different from white Europeans .
He did speculate on the admixture of Aryan or Hamitic blood arising from the advent of Islam among the Hausa and Fulani .
He reasoned that black Africans were very different from white Europeans , although he did speculate on the admixture of Aryan or Hamitic blood arising from the advent of Islam among the Hausa and Fulani .