The Vitality of Toads enclosed in Stone and Wood. 273 



some months. The greater number of those in the larger cells of 

 porous limestone were alive. No. 1, whose weight when immured 

 was nine hundred twenty four grains, now weighed only six hundred 

 ninety eight grains. No. 5, whose weight when immured was one 

 thousand one hundred and eight five grains, now weighed one thou- 

 sand two hundred and sixty five grains. The glass cover over this 

 cell was slightly cracked, so that minute insects might have entered ; 

 none, however, were discovered in this cell ; but in another cell, 

 whose glass was broken, and the animal within it dead, there was a 

 large assemblage of minute insects, and a similar assemblage also on 

 the outside of the glass of a third cell. In the cell No. 9, a toad 

 which, when put in, weighed nine hundred eighty eight grains, had 

 increased to one thousand one hundred and sixteen grains, and the 

 glass over it was entire ; but as the luting of the cell within which 

 this toad had increased in weight was not particularly examined, it is 

 probable there was some aperture in it, by which small insects found 

 admission. No. 11, had decreased from nine hundred thirty six 

 grains to six hundred fifty two grains. 



When they were first examined in December, 1826, not only were 

 all the small toads dead, but the larger ones appeared much emacia- 

 ted, with the two exceptions above mentioned. We have already 

 stated that these probably owed their increased weight to the insects, 

 which had found access to the cells and become their food. 



The death of every individual of every size in the smaller cells 

 of compact sandstone, appears to have resulted from a deficiency in 

 the supply of air, in consequence of the smallness of the cells, and 

 the impermeable nature of the stone ; the larger volume of air origi- 

 nally enclosed in the cells of the limestone, and the porous nature of 

 this stone itself (permeable as it is slowly by water and probably also 

 by air) seems to have favored the duration of life to the animals en- 

 closed in them without food. 



It should be noticed that there is a defect in these experiments, 

 arising from the treatment of the twenty four toads before they were 

 enclosed in the blocks of stone. They were shut up and buried on 

 the 26th of November, but the greater number of them had been 

 caught more than two months before that time, and had been impris- 

 oned altogether in a cucumber frame placed on common garden 

 earth, where the supply of food to so many individuals was probably 

 scanty, and their confinement unnatural, so that they were in an un- 

 healthy and somewhat meagre state at the time of their imprisonment. 



Vol. XXIII.— No 2. 35 



