' 



lMf.t r . w *nvv* at UM eompwte doobw drcuUtioo of MM 

 <*> aarflllnK to which *O*M of UM ten* jo* dacriUd 

 HL la all of Um UM Mood arriv.* 

 of .11 nut* of UM body by two UTR 



r. from which HbraoaiTwl 



M*llrtjlascK and' UMpa*M. into UM right ventricle. The 

 tat* .isitriil., by aoatoaetfakf. form* H into UM pulmonary artery, in 

 wtas* braxdMs ft If exposed to UM air, and pssssi from them to 



wins, which open into the left auricle, from which 

 It proBsii to UM Mt ventricle, thence through the single aorta 

 into all parta of UM system, and again into the vein* and right 



W* may now oon*Mr UM anatomy of the heart, and the chief 

 pcMtntMoa of UM circulation, in Kan.* Tb* heart is of a somewhat 

 oaical form, having ite baas directed backward* toward* the spine, 

 Ski las point forwards, down ward*, and to the left aide, so that at each 

 it Buy b* Mt striking between the fifth and sixth ribs, 

 i from UM middle line. It rate upon the diaphragm 

 partition batsmen the chest and abdomen, and 

 i which it lies is much flattened. It is firmly attached 

 at ite rixht aid* and behind by the inferior 

 through that muscle at the aperture 6; and 

 loosely, to the upper 

 L vessels, which there 

 i united to the surrounding cellular 



aad organ*. Everywhere else it is quite free and moveable, 

 UM nags of ite motions i* limited by the pericardium, or 

 bag in which it to contained, and which dosely surrounds 

 it at all tinea. When the heart to exposed by cutting open the front 

 of UM prieardram, it to seen to be divided along ita front and moct 



rtaeeaponwh 



Uufe 



above aid Uhmd it to Axed, though more loo. 

 astd back part of UM cheat by UM rest of ite great < 

 pax out of UM pericardium, and are united to the i 



ooaivwx surho* by a line running from the middle of ite base down- 

 wards to UM right akb of ite apex. This line and a similar one on 



. At UM base, above and on each side, two 

 s*o. Men having a little fle*by pendulous 

 ; UMS* are UM auricMS. Thu. may be seen at 



> *tt*ian*w will b* 

 fs at ita roriMr ; 



right ntriew (t) and vratrieU <) on UM right side and front 

 of UM IMS*. sad a tail aaricU (/) and ventricle (?) on ita left side and 

 thioknass of UM walls of the latter they 

 cavities will be 



Tba right anterior, or pulmonary, 



of Uds doabia heart b *xdnaiv*ly for UM dreuUtim, through the 

 p (a, A); UM Ml poatorior. or systemic, for that through the 



Mkhtd. from UM greater thioknass of UM walls of th 

 fam UM larpr porti** of UM whoU heart, but UM cavi 

 fend to U Bsarly of UM same aba. Tba right anterior, or 



_ to the vma oava inferior (,'' >, 

 to owed from UM abdomen and lower 

 Mm win b* *m to b* surrounded by a few 

 - - us with those of UM auricle itaelf, and that 

 to partially guard*! by a thin artnilunar mem- 



Tcarefltolarfirofeer 



HEAHT. ! 



branous fold called the Eiistachian valve, varying much iu size and 

 often much torn. The left side of the cavity, on the partition which 

 separates it from that of the right auricle, presents an oval depression, 

 (the fossa ovalis) surrounded by an elevated border, indicating the 

 situation of the foramen ovale, through which during the footal state 

 the blood, which was prevented by the Eiistachian valve from passing 

 into the ventricle, was conveyed directly from the right into the left 

 auricle, and thence into the left ventricle. Lastly, at the anterior and 

 left angle of the cavity another and the largest aperture (e) is seen, 

 which lead* into the right ventricle, and has attached to ita sides a 

 membranous curtain (</), by which it is occasionally closed, and which 

 is called the tricupid valve. The general form of the cavity of the 

 ri.'ht auricle is that of a quadrangular sac, from the right and interior 

 part of which a small flattened triangular process stands out. from the 

 remote similarity of which to the ear (auris) of a dog the cavity 

 ha* received ita name. Ite interior i* tolerably smooth behind, by 

 the orifice of the superior cava, on the partition, and about the opening 

 into the ventricle ; but to the right and front side, about the 

 auricular appendage and the inferior oava, it is rendered um-vrii by 

 prominent band* of muscular fibres (the musculi pectinati) whii-h 

 seem to radiate from the auricles. 



Proceeding in the course of the circulation, a cut should be made 

 from the right auricle through the aperture leading from it into tl.o 

 right ventricle, and along the front of the heart nearly to its apex ; and 

 then another from the end of the first upwards into the pulmonary 

 artery, as it arise* from the front and upper part of the ventricle, liy 

 raising the portion thus cut out, a complete view of the cavity of the 

 right or pulmonary ventricle, and of its communication with the 

 auricle, will be seen. The cavity of the right ventricle has a some- 

 what conical form, with ita base uppermost; that part of iU wall* 

 which is formed by the septum projecting somewhat into it. Its walls 

 are rendered extremely irregular by prominent bands of muscular 

 fibre* crossing each other iu every direction, and inclosing spaces of 

 various size and form, which after death are generally found filled 

 with coagulated blood entangled in and adhering to them. Here and 

 there stead* out short columns of muscle projecting into the interior, 

 and pointing towards the right auricle; these are called colututiin 



a, a, a, a, the columnir carncn ; i, b, *, i, chorda) tondinoir ; r, r, r, r, valve*. 



', and they have attached to their summits fine tendinous cords 

 (chorda tendimw), which pass thence to be attached to the edges of 

 the curtain-like membrane (the tricunpid valve) which guards the 

 orifice between the auricle and ventricle. Thin orifice is of a broadly 

 oval form, surrounded by a ring of firm di'ii-o tixiiue, to the whole 

 interior circumference of which is attached the fold of membrane, 

 trangthcnod by tendinous fibres, forming the valve. The edges of 



