"The results of our experiments amount to this: all the Toads, both large and small, inclosed in sandstone, and the small Toads in the limestone also, were dead at the end of thirteen months. Before the expiration of the second year all the large ones also were dead; these were examined several times during the second year through the glass covers of the cells, but without removing them to admit air; they appeared always awake, with their eyes open, and never in a state of torpor, their meagreness increasing at each interval in which they were examined, until at length they were found dead; those two also which had gained an accession of weight at the end of the first year, and were then carefully closed up again, were emaciated and dead before the expiration of the second year. "At the same time that these Toads were inclosed in stone, four other Toads of middling size were inclosed in three holes, cut for this purpose on the north side of the trunk of an apple-tree; two being placed in the largest cell, and each of the others in a single cell. The cells were nearly circular, about five inches deep and three inches in diameter; they were carefully closed up with a plug of wood, so as to exclude access of insects, and apparently were air-tight; when examined at the end of a year, every one of the Toads was dead, and their bodies were decayed. "From the fatal result of the experiments made in the small cells cut in the apple-tree and the block of compact sandstone, it seems to follow that Toads cannot live a year excluded totally from atmospheric air; and, from the experiments in the larger cells within the block of oolitic limestone, it seems also probable that they cannot survive two years entirely excluded from food; we may therefore conclude that there is a want of sufficiently minute and accurate observation in those so frequently recorded cases, where Toads are said to be found alive within blocks of stone and wood, in cavities that had no communication whatever with the external air. The fact of my two Toads having increased in weight at the end of the year, notwithstanding the care that was taken to inclose them perfectly by a luting of clay, shews how very small an aperture will admit of insects sufficient to maintain life. In the cell No. 5, where the glass was slightly cracked, the communication though small was obvious, but in the cell No. 9, where the glass cover remained entire, and where it appears certain, from the increased weight of the inclosed animal, that insects must have found admission, we have an example of these minute animals finding their way into a cell to which great care had been taken to prevent any possibility of access.