276 8 The Vitality of Toads enclosed in Stone and Wood. 
» It remains only to consider the case, (of which I know not any 
authenticated example), of toads that have been said to be found in 
cavities within blocks of limestone to which, on careful examination, 
no access whatever could be discovered, and where the animal was ab- 
solutely and entirely closed up with stone. Should any such case ever 
have existed, it is probable that the communication between this cavity 
and the external surface had been closed up by stalactitic incrustati 
after the animal had become too large to make its escape. A simi- 
lar explanation may be offered of the much more probable case of a 
live toad being entirely surrounded with solid wood. In each case 
the animal would have continued to increase in bulk so long as the 
smallest aperture remained by which air and insects could find ad- 
mission ; it would probably become torpid as soon as this aperture 
was entirely closed by the accumulation of stalactite or the growth of 
wood ; but it still remains to be ascertained how long this state of 
torpor may continue under total exclusion from food, and from exter- 
nal air: and although the experiments above recorded shew that life 
did not extend two years in the case of any one of the individuals which 
. formed the subjects of them, yet, for reasons which have been spe- 
cified, they are not decisive to shew that a state of torpor, or suspend- 
ed animation, may not be endured for a much longer time by toads 
that are healthy and well fed up to the moment when they are finally 
cut off from food, and from all direct access to atmospheric aire ~ 
The common experiment of burying a toad in a flower-pot cover- 
ed with a tile, is of no value, unless the cover be carefully luted to 
the pot, and the hole at the bottom of the pot also closed, so as t0 
exclude all possible access of air, earthworms and insects. Ihave 
heard of two or three experiments of this kind, in which these pre- 
cautions have not been taken, and in which, at the end of a year, the 
toads have been found alive and well. a 
Besides the toads enclosed in stone and wood, four others were 
placed each in a small basin of plaster of Paris, four inches deep 
and five inches in diameter, having a cover of the same material care- 
fon luted round with clay ; these were buried at the same time and 
in the same place with the blocks of stone, and on being examined 
-at the same time with them in December, 1826, two of the toads 
were dead, the other two alive, but much emaciated. _We can only 
collect from this experiment, that a thin plate of plaster of Paris is 
permeable to air in a sufficient degree to maintain the life of a toad 
for thirteen months. ea 
