Ao 
heart 
mechanically. (See cuts under Astaci&x and Balanof/los- 
BUS.) In the process of development one or both orifices 
of this bulb are furnished with a valve permitting the flow 
of blood in one direction and preventing it in the other ; 
and the bulb is partly divided by a constriction across it, 
one of the resulting parts being specially devoted to the 
reception of blood, as from a vein, and its transmission 
only into the other part, which then by contraction urges 
it onward, as into an artery. This is the structure of the 
two-chambered or bilocular heart of the lower vertebrates, 
in which the receiving-chamber is the auricle, the distrib- 
uting-chamber is the ventricle, and the communication 
between them is the auriculoventricular opening. In a 
more complex form the bilocular heart is partly divided 
into right and left halves by a constriction or partition 
which separates the single auricle into two, the result 
being the three chambered or trilocular heart, in which 
one auricle, the right, receives venous blood from the 
body at large, the left auricle receives aerated or arterial 
blood from gills or lungs, and each auricle pours its 
blood through its own auriculoventricular orifice into 
a common and single ventricle, which then sends a cur- 
rent of mixed venous and arterial blood to all parts of 
the body. Such is the type of the reptilian heart ; though 
the right and left auricles are in fact incompletely sep- 
arated from each other, retaining an interauricular open- 
ing, which in the embryos of birds and mammals is 
known as the foramen ovale. Finally, the entire sepa- 
ration of the auricles, and complete division of a com- 
mon ventricular cavity into a right and a left ventricle 
by an interventricular septum or partition, result in the 
perfectly four-chambered or quadrilocular heart of all 
adult vertebrates above reptiles. Here the right and left 
sides of the heart, each consisting of an auricle and a 
ventricle, are entirely separate, so that no mixture of ve- 
nous and arterial currents Is possible. (See circulation of 
the blood, under circulation.) The ventricles are larger and 
more muscular than the auricles, since the former have to 
drive the blood through the body, while the auricles have 
only to inject it into the ventricles. All the orifices of the 
heart are more or less completely guarded by sets of valves. 
The right auriculoventricular valves are called tricuspid; 
the left, mitral : in both cases from their form in the hu- 
man heart* in which three membranous valves on the right 
side and two on the left are operated by delicate fibrous 
cords (the chordae tendinece) and certain muscular pro- 
cesses from the ventricular walls (the columnce carnece). 
The orifices of the aorta and of the pulmonary artery are 
alike guarded by three crescentic valves, called, from their 
shape, the semilunar valves. The orifices by which veins en- 
ter either auricle either are or are not provided with valves, 
in different cases, or in different animals. The contraction 
of the muscular walls 
of the heart as a 
whole, or of any one 
of its chambers, is the 
systole ; the corre- 
sponding and alter- 
nating dilatation of 
its cavities, or any one 
of them, is the dias- 
tole ; the two move- 
ments together are a 
pulsation or heart- 
beat. In vertebrates 
the heart is situated in 
the thorax, between 
the lungs, and envel- 
oped in a serous mem- 
brane, the pericardi- 
um, which is gener- 
ally a closed sac with 
one layer, the visceral 
or cardiac pericardi- 
um, orepicardium, in- 
vesting the whole sur- 
face of the organ and 
the roots of the great 
vessels which spring 
from it, and the other, 
the parietal layer, re- 
flected over the sur- 
face of adjacent struc- 
tures. The primitive 
position of the heart is 
always median ; but 
in the course of its 
development from the 
embryo it generally 
becomes tilted over to 
one side, the left, as is 
usual in the higher 
vertebrates, where the 
point or apex of the 
organ lies consider- 
ably to the left, and 
the whole organ be- 
comes unsymmetri- 
cal both in its own 
shape and in its rela- 
tive position. In 
general the form of 
the heart is conoidal, 
With the base (the I. Left side, left auricle and ventricle 
auricles) upward Or laid pen: LA, left auricle; Z.K, left 
forward nn<1 trip a^pv ventricle; at>, a style passed through left 
lorward, ana tne^apt x. ventricle into aortai J^. cd> style J^g^ 
from left ventricle into left auricle, 
through left auriculoventricular open- 
: ~ig, guarded by Afy, the mitral valve ; 
. P", Py, four pulmonary veins entering 
left auricle from the lungs ; PA, pul- 
, monary artery issuing from right ventri- 
ill greatest width, and cle, not opened, RV ' ; RA, right auricle, 
2 inches in greatest scarcely seen. II. Right side, right au- 
Hpnfh n weiehs 10 or ncl ? and ventncle lai(i ?P en J ? cs > su - 
1 perior vena cava ; VCI, inferior vena 
IS m the male, C ava, these both entering right auricle, 
as shown by styles fe, cd ; Rl 7 , right 
ventricle, with PA, pulmonary artery, 
issuing from RV in course of the style 
gh, guarded by SL, the semilunar 
valves, at base of the artery; ab, style 
passed from Xt^into RA, through right 
.uriculoventricular opening, guarded by 
K, tricuspid valve ; LA, LI/, left auri- 
II. 
nan Heart Dissected. 
(the ventricles) down- 
ward or backward 
and sinistral. In man 
the heart is about 5 
inches long, 3 inches 
i ; it ! 
12 ounces 
and 8 or 10 in the 
female. It lies ob- 
liquely in the chest, 
with its broad fixed 
base uppermost, a lit- 
tle backward and to 
right ; its 
apex downward, for- aorta. 
> , , 
cle and left ventricle, scarcely seen; ,<, 
2756 
ward, and to the left, so that its beating may be seen or 
felt at a point an inch or less to the inner side of, and 
about an inch and a half below, the left nipple, between 
the tilth and sixth ribs. All the cavities of the heart are 
lined with a thin smooth membrane, the endocardium, 
which also invests the valves and is directly continuous 
with the lining of all the vessels which enter or leave the 
heart. Its substance, the myocardium, is almost entirely 
muscular; the muscle is a peculiar striated one, of a 
deep-red color ; its libers are intricately disposed in two 
sets, auricular and ventricular, separated by fibrous rings 
which surround the auriculoventricular orifices. It is sup- 
plied with blood for its own nourishment by the right and 
left coronary arteries, the first branches of the aorta ; they 
are accompanied by cardiac veins. Its nerves are derived 
from the cardiac plexuses, formed by the pneumogastric 
and sympathetic nerves. Its action is involuntary. In 
all other mammals, and in birds, the heart is substantially 
the same as in man, with differences in relative size, in 
shape, and in the detail of its openings and valves ; but 
in the acranial vertebrates, the lancelets, it is rudimentary. 
See also cuts under circulation, embryo, lung, and thorax. 
At his herte he saw a knif 
For to reuen him hise lif. Havelok, 1. 479. 
Why do I yield to that suggestion 
Whose horrid image doth unfix my hair, 
And make my seated heart knock at my ribs, 
Against the use of nature? Shak., Macbeth, i. 3. 
2. The human heart or breast considered as the 
seat of all or of some of the mental faculties ; 
hence, in common figurative use, these facul- 
ties themselves, (a) The emotions and affections, es- 
pecially moral capacity or disposition, as for love or hatred, 
benevolence or malevolence, pity or scorn, courage or fear, 
faith or distrust, etc. 
Men clepen it Mount Joye ; for it zevethe joye to Pil- 
grymes hertes, be cause that there men seen first Jerusa- 
lem. Mandeville, Travels, p. 94. 
The whole head is sick, and the whole heart faint. 
Isa.L 5. 
All offences, my lord, come from the heart; never came 
any from mine that might offend your majesty. 
Shak., Hen. V., iv. 8. 
Kind hearts are more than coronets, 
And simple faith than Norman blood. 
Tennyson, Lady Clara Vere de Vere. 
(&) The intellectual faculties ; especially, inmost or most 
private thought ; innermost opinions or convictions ; gen- 
uine or intense desire or sentiment: as, she despised him 
in her heart; the heart of a man is unsearchable; the 
devices of the heart; to set one's heart upon something. 
Merlin thought wele in his herte that so sholde it not 
go. Merlin (E. E. T. 8.), iii. 609. 
What his heart thinks his tongue speaks. 
Shak., Much Ado, iii. 2. 
(c) Good feeling ; love ; kindness ; sensibility : as, she is 
all heart; he is all head and no heart; to gain one's heart; 
to give the heart to God. 
Miss Carolina Wilhelmina Amelia Skeggs has my warm 
heart. Goldsmith, Vicar, xii. 
That vivacious versatility 
Which many people take for want of heart. 
Byron, Don Juan, xvi. 97. 
Evil is wrought by want of thought, 
As well as want of heart. 
Hood, The Lady's Dream. 
(rf) Courage ; spirit ; determination ; firmness of will ; ca- 
pacity for perseverance or endurance: as, to take heart; 
his heart failed him. 
ffor no man of lowe berthe durst not vmlirtake no soche 
dedes, but yef it come of high herte. 
Merlin (E. E. T. 8.), ii. 222. 
A faint heart ne'er wan a fair ladle. 
Jock o' the Side (Child's Ballads, VI. 85). 
" Sir," said the least, "I am almost beat out of heart." 
Bunyan, Pilgrim's Progress, ii., The Hill Difficulty. 
Being so clouded with his grief and love, 
Small heart was his after the Holy Quest. 
Tennyson, Holy Grail. 
(e) The breast, as covering the heart, considered as the 
seat of affection. 
Then let me hold thee to my heart, 
And ev'ry care resign. 
Goldsmith, Hermit, 1. 39. 
Hound my true heart thine arms entwine. 
Tennyson, Miller's Daughter. 
3. The inner part of anything; the middle or 
center: as, the heart of a country or a town. 
For it is the Herte and the myddes of all the World. 
Mandeville, Travels, p. 2. 
A goodly apple rotten at the heart. 
Shak., M. of V., i. 3. 
Y e m r durst not put to sea, till he saw his men begine 
to recover, and y e hart of winter over. 
Bradford, Plymouth Plantation, p. 100. 
The year 1740, still grim with cold into the heart of 
summer, bids fair to have a late poor harvest. 
Carlyle, Frederick the Great, HI. 7. 
4. The chief, vital, or most essential part ; the 
vigorous or efficacious part; the core. 
The very heart of kindness. Shak., T. of A., i. 1. 
Veracity is the heart of morality. Huxley, Universities. 
5. A person, especially a brave or affection- 
ate person : used as a term of encouragement, 
praise, or endearment. 
Ah, dear heart, that I were now but one half hour with 
you. J. Bradford, Letters (Parker Soc., 1863), II. 110. 
Cheerly, my hearts. Shak., R. and J., i 5. 
heart 
6. Strength; power of producing; vigor; fer- 
tility : as, to keep the land in heart. [Obsoles- 
cent.] 
That the spent earth may gather heart again. Dryden. 
Care must be taken not to plough ground out of heart, 
because if 'tis in heart, it may be improved by marl again. 
Mortimer. 
7. Something that has the shape or form of a 
heart ; especially, a roundish or an oval figure 
or object having an obtuse point at one end 
and a corresponding indentation or depression 
at the other, regarded as representing the fig- 
ure of a heart; especially, such a figure on a 
playing-card. 
"This token, which I have worn o long," said Faith, 
laying her tremulous finger on the Heart, "is the assur- 
ance that you may." Hawthorne. 
8. One of a suit of playing-cards marked with 
such a figure. 
Clubs, Diamonds, Hearts, in wild disorder seen, 
With throngs promiscuous strow the level green. 
Pope, R. of the L., iii. 79. 
9. pi. A game of cards played with the full 
pack by four persons. The rules are the same as in 
whist, except that there are no partners and no trump, 
and that the tricks count nothing, but at the end of the 
hand the player who has taken the fewest heart* receives 
a counter from each of the others for each heart that other 
has taken. The game is also played with variations from 
these rules. 
10. Naut., a block of hard wood in the shape 
of a heart for the lanyards of stays to reeve 
through. 11. In bot., the core of a tree; the 
solid central part without sap or albumen. See 
heart-wood At heart, in real character or disposition ; 
at bottom ; substantially ; really : as, he is good at heart. 
The Pharisee the dupe of his own art, 
Self-idolized, and yet a knave at heart. 
Cowper, Expostulation, 1. 94. 
Branchial heart. See branchial. Brokenness of 
heart. See brokenness. By heart, by rote ; inthemem- 
ory : as, to have, getj or learn by heart. 
Major Matchlock . . . served in the last civil wars, and 
has all the battles by heart. Steele, Tatler, No. 132. 
Shall I, in London, act this idle part ? 
Composing songs, for fools to get by heart ? 
Pope, Imit. of Horace, II. ii. 126. 
Cockles of the heart. See cockle?. Douglas heart, 
a jewel having the form of a heart, made more or less in 
imitation of the celebrated case in which Douglas inclosed 
the heart of Bruce for transport to the Holy Land. A 
number of such jewels of great richness have been pre- 
served ; they generally bear the arms of Bruce mingled 
with the arms or devices of the house of Douglas. Feast 
of the Sacred Heart, a Roman Catholic feast celebrated 
on the Friday after the octave of Corpus Christi. For 
one's heart, for one's life ; if one's life were at stake. 
I bade the rascal knock upon your gate, 
And could not get him for my heart to do it. 
Shak.,T. of the S., i. 2. 
'Heartt, 'sheartt, a minced oath or asseveration, con- 
tracted from by God's heart. 
Lady P. Not mine, in good sooth. 
Hot. Not yours, in good sooth ! 'Heart, you swear like 
a comfit-maker's wife! Shak., 1 Hen. IV., Ui. 1. 
'Heart ! stand you away, an you love me. 
B. Jonson, Every Man in his Humour, ii. 1. 
Heart alive ! an exclamation of surprise or impatience. 
[Colloq.] 
Why, what's this round box? Heart alive, John, it's a 
wedding-cake ! Dickens, Cricket on the Hearth, p. 20. 
Heart Of hearts, inmost heart ; warmest affections. 
Give me that man 
That is not passion's elave, and I will wear him 
In my heart's core, ay, in my heart of heart, 
As I do thee. Shak., Hamlet, iii. 2. 
Like most parents, in my heart of hearts I have a fa- 
vourite child. That child is David Copperfleld. Dickens. 
Heart of Mary. See Immaculate Heart, below. Heart 
Of oak, a brave heart ; a courageous person. 
But here is a doozen of yonkers that have hearts of oake 
at fourescore yeares. 
Old Meg of Herefordshire (1609). (S ares. ) 
Heart of oak are our ships, heart of oak are our men, 
We always are ready, steady boys, steady, 
Well fight, and we'll conquer again and again. 
Hearts of Oak, Universal Mag., March, 1760, p. 152. 
Heart's content. See content!. Immaculate Heart, 
in the Bom. Cath. Ch., the physical heart of the Virgin 
Mary, to which religious veneration is paid, as being united 
to her personality and a symbol of her charity and virtues. 
This veneration in its present form dates from the latter 
part of the seventeenth century. Sacred Heart, in the 
Rom. Cath. Ch., the physical heart of Christ, to which 
special devotion is offered as being not mere flesh, but 
united to and inseparable from the divinity of Christ, and 
as a symbol of his love and spiritual life. This devotion 
in its present form dates from the latter part of the seven- 
teenth century, and is approved by papal decrees. A num- 
ber of orders, congregations, etc., have been established 
in dedication to the Sacred Heart their constitutions and 
principles being in the main those of the Jesuits. Sisters 
of the Sacred Heart of Mary. See sisterhood. Smok- 
er's heart, a morbid condition of the heart produced by 
the continued and excessive use of tobacco, manifesting 
itself by disordered and inefficient action. Also called 
tobacco-heart. 
The frequent existence of what is known as smoker's 
heart in men whose health is in no other respect disturbed 
is due to this fact [the depressing action of tobacco on the 
heart]. Science, XII. 223. 
