Cha?. Ill T/je Anatomj of a UOKSE. 25 



§ II. of the Heart a^id Pericardiuirij &c. 



The Pericardium h that Bag in which ^^e Pericardi- 

 the Heart is inclofed, as in a Purfe. It riles "m, or Purfe of 

 from the Bafis, or upper Part of the Heart, '^'^^ Heart. 

 from the outer Coats of the great Vellels, which fpring 

 originally from i\\Q Pleura. It is of a middle Subftance, 

 neither very hard, fo as to hurt the Lungs, nor yet fo 

 foft as to be itfelf eafily injur'd by the Motion of the Heart. 

 It is perforated in five Places, namely, on the right Side, 

 for the afeending Trunk of the Cava., which commg from 

 the Liver, enters the right Ventricle., and by the Sub' 

 clavian Vein, which defcends by the Channel-bones into 

 the fame Ventricle ; and thirdly, by the Pulmonary Axitry.^ 

 which goes out of the right Ventricle into the Lungs : On 

 its left Side it is perforated for a Paflage to the Pulmonary 

 Vein, which comes from the Lungs, and enters the left 

 Ventricle : And, lallly, for the great Artery that pafles out 

 of the faid Ventricle. 



ItsVeins are from the Phrenick and Au^il- Its Vejfds. 

 liaries ; its Arteries are fo fmall, that they are 

 not very difcernable ; its Nerves come from the Parvagum* 



The Ufe of this Purfe or Bag, is to cover j rj^ 

 ■the Heart, and be a Defence to it, to contain 

 a Moifture not only to keep it glib and eafy in its Motion, 

 but alfo cool. There are various Opinions concerning, 

 this Liquor of the Pericardium^ and from whence it is de- 

 rived ; but I fliall not give the Reader any Trouble by re- 

 citing them, but haften to the Heart itfelf. 



The Heart is the principal Fountain The Heart. 

 which fends Blood and Nouriftiment into 

 all Parts of the Body, and is wonderfully fuited in every 

 Refpefl for that Purpofe. 



It is fituated in the Midft of the Cheft, where it is en- 

 compafled by the Lobes of the Lungs, having its Point in- 

 clining to the left Side. It is in Shape not very different 

 from what it is in moll other Animals, only in a Horfe it 

 does not grow gradually narrow towards its Point, as in 

 Ibme, nor fo broad in Proportion at its Bafis or Root. 



Its Subftance is Hefhy aad very folid, that j^^ Suhftance 

 u may the better endure the Perpetuity of 

 Motion, and expel the Blood with more Force to all Parts of 

 the Body. It is for that Purpofe compofed of mufcular and 



