Strongarm’s leadership illustrates the natural leadership of the most fit in time of danger. At other times, without doubt, there was no recognized leader. _References_: Katharine E. Dopp, _The Place of Industries in Elementary Education_, pp. 22-27. Chicago: The University of Chicago Press. _The Tree-Dwellers_, pp. 115, 119-121, 156, 157. Chicago: Rand, McNally & Co. _Lesson VI._ The manners of the cave-men at the feast may be understood when it is remembered that the food supply of hunting peoples is irregular. Their lack of forethought is such that there is either a feast or a famine. Besides, their digestive systems were so well developed that it was possible for them to eat enormous quantities without harm. The habit of eating together developed slowly and probably depended largely upon the degree to which coöperative action was used in hunting. Except upon extraordinary occasions we may conclude that only those ate together who worked together in securing food. Encourage the child to make a collection of as many things as he can find that he can use for or make into dishes. If the child is allowed to crack the marrow bones of a chicken or turkey and make soup of them, he will understand the liking of the cave-men for marrow bones. The conversion of bones into musical instruments played by striking, or into bone whistles, may also furnish a delightful occupation which may yield results of no mean value. _Lesson VII._ Let the children dig cooking-pits and caves of various sorts in the ground and experiment with them to discover where the smoke goes and why, and the effect of the form of the cave or cooking-pit upon the draft. The invention of a means of carrying off the smoke, and the attempt to regulate the draft in these crude contrivances, will lead to an interest in the fireplaces and chimneys in the child’s own house. Make use of this interest in such a way as to lead the child to observe the materials used and forms adopted in the construction of modern fireplaces and chimneys, and encourage him to seek reasons for the same. Show the child a picture of the interior of a cave that has stalagmites and stalactites, and illustrate their formation by dissolving rock salt or lime in water and letting it drip until a deposit is made.