So the people using them heated the water in which the food or the soup was boiled by making stones red-hot in the fire and then dropping them into the birch-bark or cedar-wood tubs.

Many of the northern Indians got into the way of eating their food raw because of the difficulty of making a fire away from home.
In regard to food, neither Amerindian nor Eskimo was squeamish.

They were almost omnivorous, and specially delighted in putrid or noisome substances from which a European would turn in loathing, and from the eating of which he might conceivably die.
It was only in the extreme south of Canada or in British Columbia (potatoes only) that any agriculture was carried on and that the natives had maize, pumpkins, and pease to add to their dietary; but (as compared to the temperate regions of Europe and Asia) Nature was generous in providing wild fruits and grain without trouble of husbandry.

The fruits and nuts have been enumerated elsewhere, but a description might be given here of the "wild oats" (_Avena fatua_) and the "wild rice" of the regions of central Canada and the middle west.
The wild oats made a rough kind of porridge, but were not so important and so nourishing as the wild rice which is so often mentioned in the stories of the pioneers, who liked this wild grain as much as the Indians did.
This wild rice (_Zizania aquatica_) grew naturally in small rivers and swampy places.

The stems were hollow, jointed at intervals, and the grain appeared at the extremity of the stalk.