Numerous experiments have been made with a view to test the possibility of these reputed facts. If Toads do so commonly become voluntarily or accidentally immured, and remain without light, food, or even air, for many years, and yet survive, let us put some Toads into similar circumstances, keep them shut up, and, after the lapse of a sufficient interval, examine them, and see whether they are alive or dead. "_Experimentum faciemus in corpore vili_," as the village doctor said to his assistant over the sick traveller. _Probatum est!_ Besides the case mentioned in Mr Bartlett's letter (_ante_, p. 149), the late Dr Buckland, in November 1825, instituted a series of careful experiments, which are thus narrated by himself:--"In one large block of coarse oolitic limestone, twelve circular cells were prepared, each about one foot deep and five inches in diameter, and having a groove or shoulder at its upper margin fitted to receive a circular plate of glass, and a circular slate to protect the glass: the margin of this double cover was closed round and rendered impenetrable to air and water by a luting of soft clay. Twelve smaller cells, each six inches deep and five inches in diameter, were made in another block of compact siliceous sandstone, viz., the Pennant Grit of the coal formation near Bristol; these cells also were covered with similar plates of glass and slate, cemented at the edge by clay. The object of the glass covers was to allow the animals to be inspected, without disturbing the clay so as to admit external air or insects into the cell. The limestone is so porous that it is easily permeable by water, and probably also by air; the sandstone is very compact. "On the 26th of November 1825, one live Toad was placed in each of the above-mentioned twenty-four cells, and the double cover of glass and slate placed over each of them, and cemented down by the luting of clay. The weight of each Toad in grains was ascertained and noted by Dr Daubeny and Mr Dillwyn at the time of their being placed in the cells; that of the smallest was 115 grains, and of the largest 1185 grains. The large and small animals were distributed in equal proportion between the limestone and sandstone cells.