Secondly, the form of the cells is by no means identical. They prefer the hexagon,--the form which is best adapted to secure the greatest possible number of cells in the smallest area. But they do not slavishly bind themselves to this form. The first comb which they attach to the framework would cling to it very insecurely, and only by its projecting edges, if it were composed of six-sided cells. They therefore make it with five sides only; and fashion it of pentagonal cells with broad bases, which attach themselves solidly to the wood on a continuous line. The whole is agglutinated and sealed, not with wax, but with their gum, or _propolis_, which, as it dries, becomes hard as iron. The great royal cellules, or cradles of the future mothers, which may be seen by the side of the combs, are not six-sided, but of the form of an oblong egg,--which secures the royal favourites considerable ease, and a great facility of development. Finally, you may, with a little attention, detect important differences among the ordinary hexagonal cells, though at the first glance they all seem alike. They are small for the industrious gleaners, larger for the artistic wax-makers, and largest for the males. This size is generally obtained by means of a little rounded fragment which is deposited in the bottom, and renders it slightly circular,--I was about to say pot-bellied (_ventru_). As the house, so the tenant; the male will come into the world a squat, obese figure,--predestined to this form by that of its cradle. Thus, of their own accord, they vary the configuration and extent of the cellules. And they vary them yet more, according to the obstacles they encounter. If room be denied them, they reduce the size of their hexagons in due proportion and with extreme address. This fact Huber verified by some ingenious experiments. He bethought himself of deranging their operations by placing, instead of wood, a plate of glass against the wall of the hive where they were building up their cells. From the distance they saw this smooth shining crystal, to which nothing could be fixed; and taking their measures accordingly, they curved their cake in such a manner that it went past the glass and joined on to the wood. But, to carry out the alteration, it became necessary to change the diameter of the cells; to enlarge that of the convex portion, and diminish that of the concave. A delicate problem! and yet it was readily solved by the skilful architects.