Mifcettanea Curiofa. 173 



them, but what is forced through them by the 

 contrary Action of fome ftronger Mufcles, which, 

 though not properly to be call'd Antagonifls, yet 

 on all neceflary Occafions perform the Office of 

 fuch. 



Thar, the Heart is a Mufcle, furnifli'd and 

 inftructed for Motion like other Mufcles, is 

 ( in my Opinion at leaft ) demoiiltrated be- 

 yond Contradiction by Dr. Lower and others. 

 And, as it is a Solitary Mufcle without any pro- 

 per Antagonift, and not directly under the pow*. 

 er of the Will, nor exercifing Voluntary Mo- 

 tion, it approaches neareft to the Sphintler kind, 

 which only has thefe Conditions in common 

 with it. But in conftant and regular Al- 

 ternations of Contra&ion and Dilatation, it dif- 

 fers exceedingly from all the Mufcles of the 

 Body. 



This reciprocal Ai/lus of the Heart has gi- 

 ven the Learned abundance of trouble ; who, 

 finding nothing peculiar in the Structure, which 

 fliou'd neccflarily occafion it, nor any Anta- 

 gonift, whole re-action (hould produce it, have 

 been extreamly perplex'd to find out the caule 

 of it. 



But pafling over the various Opinions of Au- 

 thors, to avoid being tedious, I (hall take notice 

 here only of the very Learned Dr. Lowers, in 

 whofe Account of the Syftole, however fblid and 

 ingenious, 1 obferve fbmething deficient, and 

 whofe Hypothecs of the Diaftole I think to be pre- 

 carious and falfe. 



This Excellent Author, having by found 

 Arguments drawn from the Structure and 

 Mechanifm of the Heart, eftablifh'd the Cer- 

 tainty of its Mufcular Motion, refts fatisfied, 



with- 



