(Il. cONFINED IN STAGNANT AIR. 10g 
air previoufly vitiated by exhalation. Sig. Cig. 
na had experienced this. He confined a frog in 
a receiver where five or fix were already dead : 
the frog inftantly became agitated, and leaped 
violently againft the fides of the receiver ; it was 
immediately affected by a frequent and laboured 
refpiration, which gradually became more pain- 
ful, and foon ended in death. Therefore I fully 
coincide with the Turin profeffor, that refpira- 
tion is injured; but I cannot admit that fuch a 
contraction of the organs enfues as to kill the 
animals by fuffocation. Several frogs will live 
a long time ina capacious veflel. Their vivacity 
remains more than a day if the weather is not 
warm: after this they become fluggifh, and 
{well exceflively. If males, the two veficles on 
the fides of the head increafe, and their inflation 
is fo great as to prevent the frogs from finking, 
and keeps them always on the furface of the wa- 
ter. Having remained fome time in this ftate, 
the frogs expire. On opening them, we difcover 
that the {welling proceeds from inflation of the 
lungs, which cannot poflibly be more diftended. 
The fame inflation is found in thofe of toads and 
frogs dying in this manner; and they, too, are 
neceffitated tofwim. But the lungs are fo far 
from being rigid and contracted, that they are 
much dilated and confiderably charged with air. 
For this reafon, then, and for others of which I 
fhall 
