BAT. 
343 
was surprised to find in a place covered with ala- 
baster, and so dark and profound, a kind of earth 
which was totally different. It was a thick mass 
several feet in extent, of a blackish matter, almost 
entirely composed of fragments of the wings and 
legs of flies and moths, as if immense numbers of 
these insects had assembled in order to die and cor- 
rupt together. This, however, was nothing else 
but the dung of bats, probably amassed during ma- 
ny years, in a favourite part of these subterranean 
caverns ; for, through the whole of these caverns, 
which extend nearly half a mile, he saw no other 
collection of this matter, and therefore imagined 
that the bats had fixed upon this place for their 
common abode, because it was reached by a glim-* 
mering light from an aperture in the rock ; and 
that they chose not to go further, lest they should 
be lost in a darkness too profound. Into these im- 
mense caverns they retire at the end of autumn, and 
always assemble in such numbers as to secure them- 
selves from the effects of cold : here they pass the 
winter without food or motion, in a complete state 
of torpidity. Some cover themselves with their 
wings as with a mantle, and suspend themselves by 
the hind feet from the roof of the caverns ; while 
others stick fast to the walls, or retire into holes, 
where they remain entranced till the vernal sun 
once more unlocks the earth, and recalls them 
into life and action. 
The common bat is about the size of a mouse, 
has long extended toes to the fore feet, connected 
