A number of crania and parts of crania on which trepanation had been performed have also been taken from several mounds on Chamber’s Island, from beneath the mound in the neighborhood of the Sable River, near Lake Huron, and near the Red River29 Gillman thinks that the Michigan trepanations, which bad been made with clumsy tools, were simply holes for hanging up skulls as trophies, as is still customary amongst the Dyaks of Borneo; but this seems scarcely a tenable hypothesis, for as a rule the skeletons lying in their last home are complete. Quite recently were discovered, beneath a tumulus near Rock River, eight skeletons, the skull of one of which bore a circular perforation made during life, which rather upsets Gillman’s theory. But to resume our narrative. The trepanations reported from North America are generally posthumous, and we can prove nothing as to their origin. Were they marks of honor made in some religious rite? Were they openings to allow the spirit of the departed to revisit the body it had abandoned? or, to suggest a far more worldly and revolting motive, were they merely holes through which to pick out the brains of the dead. A missionary, in a letter dated from Fort Pitt (Canada) in 1880, describes the mode of scalping practised by the Redskins, and says that they often take a round piece of skull as well as the scalp. May not this be a case of atavism, or the transmission of a custom from one generation to another, for the origin of which we must go back to the most remote ages? In the present state of our knowledge, insufficient as it is, this explanation is the most plausible.