a menstruum, which a gum, apparently of a resinous nature, is unable to resist! This fact can only be explained by the analogous insensibility of the stomach to the gastric juice, which can dissolve bone; and it is equally worthy of admiration. In both cases, the _vitality_ of the membranous or fleshy receptacle secures it from the action of the included fluid; but _how_, who shall explain?" [Illustration: _Glazed Ant-hill of M. Huber._] The naturalist, Huber, the patient historian of the ants, gives us a very interesting account of the proceedings of these wonderful insects, in actually _assisting_ the young out of their silken cases. These pupæ are enclosed in a tissue of silk, of so compact a texture, and formed of so strong a silk, as to render it impossible for the prisoner within to rupture the fibres, and get out of prison. The worker ants, therefore, are instructed by a heavenly Ruler and Guide to give help to the prisoners, and to secure their egress. But how do these indefatigable attendants ascertain precisely the moment when their aid is required? The insect within has no power of voice to cry out for help, nor those without, in all probability, the faculty of hearing, if it could do so. It seems probable that they are acquainted with it from some slight movements which take place within, which they ascertain by means of their antennæ. Whatever it be, the attendants never interfere at a wrong time. Their manner of proceeding is beautifully described in the following words of this author:--"Several males and females lay in their envelopes in one of the largest cavities of my glazed ant-hill. The labourer-ants assembled together, and appeared to be in continual motion around them. I noticed three or four mounted upon one of these cocoons, endeavouring to open it with their teeth, at that extremity answering to the head of the pupa. They began to thin it by tearing away some threads of silk where they wished to pierce it, and at length by dint of pinching and biting this tissue, so extremely difficult to break, they formed in it a vast number of apertures. They afterwards attempted to enlarge these openings, by tearing or drawing away the silk; but these efforts proving ineffectual, they passed one of their mandibles into the cocoon, through the apertures they had formed, and by cutting each a thread, one after the other, with great patience, at length effected a passage, of a line[P] in diameter, in the superior part of the web. They now uncovered the head and feet of the prisoner, to which they were desirous of giving liberty; but, before they could effect its release, it was absolutely necessary to enlarge the opening. For this purpose these guardians cut out a portion in the longitudinal direction of the cocoon, with their teeth alone, employing these instruments as we are in the habit of employing a pair of scissors. To expedite the work some raised up a little slip cut out in