92 . ANIMALS AND VEGETABLES TH. 
‘But notwithftanding the equal quantity of ‘air in 
the veffels, I conftantly found that they died 
fooner as they were more numerous; and that 
the acceleration of death was always in propor- 
tion to the encreafe of number. Thus, it is evi- 
dent, that the death of animals, in clofe veffels, 
imvariably happen fooner as the animals are more 
numerous. 
By what phyfical agent, by what means are 
they deftroyed? Is it by their breath, or perhaps 
by injuring the quality of the air which they re- 
fpire?, Let us carefully examine thefe two hypo- 
thefes, beginning with that which is founded on 
an alteration of the ftate of the air. That it does 
lofe part of its elafticity is evident from barome- 
ters put in the veflels where animals are confined, 
Stair obferved that his fell an inch in one where 
a rat died. The defcent varies. In Veratti’s 
experiments, it fometimes fell aight lines, fome- 
times nine, twelve, or more, according to the na- 
ture of the animals. The experiments of Mayow, 
Boyle, Hales, and others, agree in eftablith- 
ing that a portion of the air is deftroyed by ani- 
mals confined in a clofe veffel. We cannot con- 
clude from them, that the death of animals in 
clofe veflels is owing to the diminifhed elatticity 
of the air; at leaft there are no experiments po- 
fitively proving the fa&. It is firft neceflary to 
enquire, whether an alteration of the air always 
takes 
