( 907 ) 
in that time by confequence took in as much Air as - 
would fill up a Vefiel capacious enough to hold three 
Gallons of Water ; and it's plain that the Air expired re- 
turns much aker'd, for as much as the Breath or Hali» 
tus returns impregnated with a moift Vapour, and fuch 
a one as does many times indicate the Temper of the 
Blood : From this Halitus fmpoilhumations of the 
Lungs are frequently predi&ed : Such as have Sulphu- 
reous Blood ffaall emit no very pleafing but rancid Ex- 
halations : Nor does the Blood only clear it felf of fome 
Vapours in expiration, but alfo imbibe, and impregnate 
it felf with fuch Particles as are neceflary to maintain 
Life in infpiration ; for a Mao could not fubfift long in 
a Tun of Air, Ihould he be kept clofe in fo capacious a 
Veflel, as we have found by Experiments made with fe- 
veral refpiring Animals, Dogs, Cats, and Birds, &c* 
that thele would foon die there ; fo that we need con- 
ftant fupplies of vaft quantities of frelh Air, which 
makes me believe that thofe Particles feparated out of 
the Air by the Lungs are very fparingjy delivered or 
mix''! with the common Air, but yet with this differ- 
ence, that the more comprefs'd the Air is, the more it 
contains of that vivifying Salt or Spirit, and the contra- 
ry, the more rarified the lefs is found ; for we are told 
by the Experience of fuch as have been on the Pike of 
Teneriff^ that their breathing is more difficult there 
than at the bottom, where the Air is more comprefsU 
And we have found Birds and Mice, &c. would live as 
long again, in a VefTel where we had crouded in, by a 
Syringe ( or any other condenfmg Engine ) a double 
qu iiitity of Air, as they did Where they were confined 
only to common Air. To conclude, fince the vivifying 
Particles in the Air feem to be very fpariogly diflemi- 
nated through it, I am apt to believe that the Noxious 
and Peftikntial are more fparingly fcattered up and 
down ; ( the Author of Humane Nature having taken 
more 
