Consideration is what is done in return for a promise, sec 493.

Promise without consideration not binding, sec 494.

Exception as to sealed documents, sec 495.

Executed gift cannot be recalled, sec 496.

Distinction between "good" and "valuable" considerations, sec 497.

Cumulative promise a nullity, sec 498.

But agreement for extension or modification not cumulative, sec 499.

Promise to do what a party is bound to do is not valid, sec 500.

Question as to promise to reward duty to others, sec 501.

Agreement to pay public officer invalid, sec 502.

So of promises to give extra pay to seamen, sec 503.

Part payment no consideration for promise, sec 504.

Detriment or loss of rights to other side a consideration, sec 505.

Party suing must show consideration flowing from himself, sec 506.

Cannot recover unless on duty assumed to himself, sec 507.

Promise against policy of law not valid consideration, sec 508.

Illegal consideration vitiates, sec 509.

And so of impossible consideration, sec 510.

When considerations are divisible, illegal or inoperative may be rejected, sec 511.

Moral obligation not sufficient consideration, sec 512.

Party may waive benefit of statute, sec 513.

Executed act not a valid consideration, sec 514.

Otherwise as to continuing consideration, sec 515.

Amount of consideration not material, sec 516.

Courts will not determine sufficiency, sec 517.

Gross inadequacy may be ground to set aside, sec 518.

Consideration utterly valueless invalid, sec 519.

Money paid without consideration may be recovered back, sec 520.

Release of unliquidated debt a sufficient consideration for promise to pay a specific sum, sec 521.

One consideration can support several promises, sec 522.

Promise may sustain promise, sec 523.

Promise may be contingent, sec 524.

Promise to support illegitimate children good when on good consideration, sec 525.

Assignment of a debt a good consideration, sec 526.

Releases by other creditors sufficient consideration, sec 527.

So of mutual subscriptions to charities, etc., sec 528.

Fraud vitiates such subscriptions, sec 529.

So of interchange of patronage, sec 530.

Merely equitable rights a valid consideration, sec 531.

Forbearance of legal proceedings sufficient consideration, sec 532.

So of compromise of doubtful claim, sec 533.

So of giving up litigated document, sec 534.

Forbearance of void claims no consideration, sec 535.

Assuming indebtedness of another a valid consideration, sec 536. So of marriage, sec 537. Equity will not set aside executed gift, sec 538. In negotiable paper burden is on party disputing consideration, sec 539. Consideration may be proved or varied by parol, sec 540.