'The methods used in the German study owed a debt to the British ethnologist John Beddoe, whose “index of nigrescence” concluded that Jews were “100 per cent” Negro. Figures such as Beddoe are key to Tudor Parfitt’s latest book Hybrid Hate, which details the strange ways that race theorists developed modern modes of anti-black racism and antisemitism.'

https://www.ft.com/content/03aad35c-2d7e-41a2-8592-4fe44b5ca400