Sentence:  Those people, in regard to appearance and way of life, were so different from the White people that intermingling or <WSD>bastardization</WSD> could practically not take place. The biological position was of such a nature that there was no possibility of <WSD>bastardization</WSD>. In spite of that, <WSD>bastardization</WSD> did take place here and there, and the progeny of that <WSD>bastardization</WSD> were so far removed from the Whites, and the Whites no longer had the biological ally, if I may call it that, to help them to remain White. 
Meaning of the word marked with <WSD> tags:  The combining of separate races in marriage or breeding; miscegenation.