106 ANIMALS AND VEGETABLES III, 
kill them. I made a new experiment to afcer-— 
tain pofitively whether they were deftructive. 
The opening of the receiver was enlarged, and 
the exhalations were tranfmitted into a veflel ap- 
plied to it. In the veffel were confined two 
{wallows, and it was completely fecured by a 
wooden ftopper, well fitted. 1 preferred fwallows 
as eight had previoufly died in the receiver. ‘The 
influence of the exhalations was fuch, that both 
died in a quarter of an hour, though two confin- 
ed in a fimilar veffel lived fully two hours. 
The experiment was diverfified, by collecting 
various quantities of vapour in the veffel. Animals 
have always lived in proportion to the quantity. 
Long after the vapours are confined, they retain 
their deftructive property. Whatever animals have 
afforded them makes little difference in their in- 
fluence: they are equally fatal to all others. 
Exhalations from birds kill quadrupeds, and 
thofe from quadrupeds are deftructive of birds. 
To terminate the inveftigation, I made the fol- 
lowing experiment. Many animals having ex- 
pired in a receiver during very warm weather, I 
opened the hole at the upper part, and prefented 
a bird to the very feetid vapour which efcaped, 
fo that it was forced to infpire the mephitic air ; 
this and every one treated in the fame manner 
perifhed. 
Although, © 
