( 1240 ) 
conflaU fietufffj pjlqmm eum femel hau ferity citios fuffocari 5 
quam cum ah illo prorfus ncczbatur. The Dr, obferving a f(etm 
to live longer without Refpiration, and to difpence better 
with the want of Air while included in the Membranes en- 
tire, than it cou'd afterwards 5 infers thence, that the Air 
does in the firft Aft of Infpiration imprefs upon the Lungs 
fome quality, which renders it ever after more indifpenfably 
neceffary. But allowing his Obfervation, I muft yet deny 
his Inference to be good : For, deprive a Fcstus of means 
of refpiring, and then take it out of the Membranes, and it 
ftiall be as foon fuffocated, as if it had refpired before. 
This proves, that thisNecefTity ot intercourfe vvith the Air 
by way of the/Lungs is not the OfFsfpring, but the Parent 
of Rerpiration,and that, that Learned M^n was drawn into 
*a Fallacy oi h/on caufa pro cauf&. 
^he reafon of this Neceffity is the preflure of the External 
Air upoji the Surface ot the Body, from which it was de- 
fended by theinterpofition of theMembranesand theHumours 
contained, which are not fo comprelfible, as the Body of the 
Fcetus itfelf. So foon therefore as thcF^tus is excluded, and ex- 
posed to rhe immediate contaft of the ambient Atmofphere,the 
Veffelsand all the Cavities of the Body muft neceflarily be fo 
comprefs'd, that the Fluids can't have room for Motion, and 
confequently the F(KtHi cou d have no Life, if Nature had not 
contriv'd by the Motion of the Thorax to remove and admit 
that prelfure alternately, and thereby to imprefs a Motion 
on the Fluids, which is the Spring of Life. But this Motion 
of th^Thorax being any w'ay fupprefs'd, the equal preflure 
of the Atmofphere on all parts occafions a total Ceffation of 
Motion, w^hich is Death* 
I (ball profecute thisSubjeft no farther now,nor trouble the 
Reader with any Apology ,tordiflenting from thofe greatMen 
herein named : Becaufe, I hope, I have done it with Mbdefty, 
and all the Refpeft due to fo great Authorities, and haveaf- 
fign*d nothing which is not matter of F9£i: uncontroverted, 
or deduced from it by plain Mechanical Neceffity. 
nr. Th 
