What is "generalises"

Usage examples of "generalises".

For altho he writes particularly of the Southern Indians only, the Catawbas, Creeks, Cherokees, Chickasaws and Choctaws, with whom alone he was personally acquainted, yet he generalises whatever he found among them, and brings himself to believe that the hundred languages of America, differing fundamentally every one from every other, as much as Greek from Gothic, have yet all one common prototype.