" Explain the obsession amongst European settlers in sub-Saharan Africa with 'black' and 'yellow' perils". ISSUES OF MISCEGENATION AND RACIAL PURITY: There was a general outrage at the concept of mixed race relations within colonial Europe, especially within Britain, who did not take the same line on the subject of assimilation as their French and especially Portuguese counterparts. Although mixed relationships between white males and coloured females were tolerated, similar such relationships concerning white women were not, as this raised imperial issues of race theory and Darwinistic eugenics.