Food.
It would be difficult to discover any plant or animal life which had not served at some period for food. Primitive man knew nothing about harmful plants, and only by long experience did he learn to avoid such as worked him woe. No insect or animal is so repulsive but that it has been appropriated by the food-hunter in some age and country, and things today which we would refuse in time of distress were used as a matter of course by earlier people.
Nature supplied acorns, berries, roots, fruits, fish and plenty of game. All these articles were at first eaten in their native state. When fire became well known, cooked foods grew in favor. It is supposed that these were at first roasted. To suspend meat over a fire or make a large opening in the ground, cover the floor with stones, heat these very hot, then remove the fire and bake the food, these are the most primitive—as well, perhaps, as the most satisfactory—ways known to us. Boiling was probably a later method, and this was not done as we boil food today. Rather, stones were heated very hot and tossed into kettles of water. In this way the water was brought to a boiling point and the food cooked.