188 Mijcellanea Curio fa* 



as in all other voluntary Motions the influence 

 of the Will only gives a prevalence to one of its 

 two Powers before equilibrated, fo here it ferves 

 to enable thofe Mufcles to lift up a weight too 

 ponderous for their ftrength not fo afiifted ; 

 and therefore as foon as that afliitance is with- 

 drawn, the Ccft<e are again deprefs'd by the 

 rneer Gravitation of the Atmofpkere, which wou'd 

 otherwife remain elevated through the na- 

 tural Tendency of thofe Mufcles to Contra- 

 ction. 



This is evidently prov'd from the Torricellian 

 Experiments, and thofe made upon Animals in 

 Mr. Boyle's Engine ; where, as fbon as the Air 

 is withdrawn, and the freffure thereby taken off, 

 the Intercoftal Mufcles and Diaphragm are con- 

 tracted, and the Ribs elevated in an inftant, and 

 can't by any Power of the Will be made to fub- 

 fide, till the Air is again let in to bear them for- 

 cibly down. 



It were fcarce worth while to take notice here 

 of a Miftake of the Learned Dr. Willis 9 were it 

 not for the great Authority of the Man, which 

 is almofl: fufficient to keep Error in countenance, 



The Doctor having obferv'd, 

 J)e^efpimionis Aat the FIbres ofrhe Exterml 

 Orgmis & Vfu. ^ Intemal Jnttrcoftd Muf ^ Ies 



ran in a contrary order, as it were, decuffating 

 each other, takes occafion from thence to fanfie, 

 that there was an oppofuion in their Office 3 and 

 that as the External ferv'd to raife up the Ribs, 

 the Internal drew them down again, forgetting 

 at that time, That, when a contractile Body is 

 faften'd at the feveral ends to Points unequally 

 moveable, let the Contraction happen in what, 

 part or manner foever, the more moveable Point 



mud 



