Honestly, Iains, we're talking about the 19th Century, the age of Gobineau, Morton, Linnaeus, Agassiz, etc. etc., the flourishing of scientific racism, eugenics, and not coincidentally, of Euro-American imperialism. It seems to me absolutely fair, given the well-attested academic background, to begin with a default assumption of general, deeply held, racist ideology and assign the burden of proof to those who would dispute it in particular areas. As an American, I've been aware of my nation's racist and genocidal history since childhood, but frankly, the more I look into it, the worse it gets.

If you check out the Wikipedia article on Scientific Racism , you'll find an interesting illustration demonstrating the Irishman's kinship with the Negroid race, in contrast to the pure Teutonic features of the Englishman.

It's worse than you think.