III. cONFINED IN STAGNANT AIR. I05 
on which every one makes the life of animals 
depend, either by being decompofed or cor- 
rupted, fo as to become unfit for refpiration. 
But the flender fupport of thefe reafons is demon- 
ftrated by animals themfelves, for they die in 
fituations where the communication of the inter- 
nal and external air is uninterrupted. When feven 
frogs had died in a. receiver, I opened the ftop- 
cock, and gave admiflion to the external air to 
balance that within; in an hour, other two frogs 
were confined, the ftop-cock remaining open, 
but they died in lefs than an hour and a half. 
Further, the frogs in the receiver perifhed fooner, 
as the number of dead frogs was greater, al- 
though the diameter of the opening above was at 
leaft two lines. Several birds, reptiles, and {mal} 
quadrupeds had the fame fate when forced to re- 
main among dead animals, though the receiver 
was open above. As the communication of the 
internal with the external air was uninterrupted, 
the imagined alteration or corruption of the air 
cannot exift, and death is certainly occafioned by 
the exhalations of refpiration, fince we have feen 
that it happens when the top of the receiver is 
open, as part of them can then efcape. 
It may be remarked, in pafling, that the death 
of animals in an open receiver decifively. proves 
that the diminifhed elafticity of the air does not 
kill 
