⁵Haddon, A. C. and C. R. Browne. "The Ethnography of the Aran Islands, County Galway." Proceedings of the Royal Irish Academy, V. 2 (1891-1893). p. 780.
The authors noted, "t is not probable that the O'Briens or the O'Flaherties were Firbolgs. We know that garrisons were several times quartered on the islands, more particularly on Aranmore, and it is not improbable that owing to wrecks and to possible occasional immigrants from Galway of 'foreigners,' that mixture of blood may have occurred during the lapse of the last 500 years.'
They also noted (p. 799), “The population seems on the whole to be an unusually healthy one. Idiocy and imbecility are not common, there being but two cases on the islands, both imbeciles, but possessed of a certain amount of shrewdness.”