The subject-matter of every contract is something which is to be done, or which is to be omitted. No very precise or logical division and classification of these various things is known to the common law. The division stated and followed in the Pandects, and referred to by Blackstone, (a) is exact and rational. It recognizes four species of contracts: Do ut Des; Facio ut Facias; Facio ut Des; Do ut Facias. But this division is not, in the civil law, strictly followed. The whole subject of purchase and sale (emptio et venditio) is treated of before this division is introduced. (b) Blackstone says, "Of this kind (Do ut Des) are all sales of goods." But in fact it seems to be confined to giving a thing (not money) to receive a thing in return.

It is impossible to make much use of this classification, in exhibiting the rules of the common law in relation to contracts; and the arrangement of the subject-matters of contracts which we have adopted is the following. We shall treat of Contracts,1. For the Purchase and Sale of Real Estate.

2. For the Hiring of Real Estate.

3. For the Purchase and Sale of Chattels.

4. For the Purchase and Sale of Chattels with Warranty.

5. Of the Right of Stoppage in Transitu.

6. For the Hiring of Chattels.

7. Of Guaranty.

8. For the Hiring of persons.

(a) 2 Bl. Com. 444. See ante, p. * 430, note (n).

(b) Emptio et Venditio. Pandects, lib.

18, tit. 18. Do ut des, etc. Pandects, lib.

19, tit. 5, art. 1, § 4.

9. For Service generally.

10. Of and in relation to Marriage.

11. Of Bailment.

12. Of Telegraphs.

13. Of Patents.

14. Of Copyrights.

15. Of Trade-marks.

16. Of Shipping.

17. Of Marine Insurance.

18. Of Fire Insurance.

19. Of Life Insurance.

Before, however, considering these topics severally, a few-words may be said of the remedy which the common law affords for injury sustained by a breach of a contract to do a specific thing.

Where the thing to be done is the payment of money, there, in general, the remedy is adequate and perfect. But where the thing to be done is anything else than the payment of money, there the common law can give only a remedy which may be entirely inadequate; for it can give only a money remedy. The foundation of the common law of contracts may be said to be the giving of damages for the breach of a contract. And even where the contract is specifically for the payment of money, and for nothing else, still the law does not, generally, in form, decree an execution of the contract, but damages for the breach of it. If an action be brought upon a promissory note, or a covenant, the plaintiff sets forth the contract and the breach, and does not pray for an execution of it; but he sets forth also the damages he has sustained, and claims them. The action of debt may, it is true, be brought, not only on a bond, but upon many simple contracts; and in this action the payment of the money due is directly demanded, and such is the judgment if the plaintiff recovers; but this action is not much used at the present time, in this country at least, to enforce simple contracts. Where the contract is for any other thing than the payment of money, the common law knows no other than a money remedy; for it has no power to enforce the specific performance of a contract, with the exception only of those money contracts for which debt will lie.

This inability of the common law was among the earlier and most potent causes which gave rise to courts of equity; for * these courts have, both in England and in this country, a very complete jurisdiction over this class of cases. Perhaps this apparent defect in the common law may be explained, by supposing that, originally, the action of debt gave the power of compelling performance in fact, in the great majority of cases which required it, and that the comparative disuse of this action, and the coming into notice of the great variety of other cases in which this power was needed to do justice, occurred after the forms of the common law had become fixed, and when there was a great unwillingness in the courts to change or enlarge them, and when also another court had grown up which had full power in all such cases. However this may be, this defect in the common law, which must be felt more and more sensibly as society advances beyond the point at which it is willing to measure all rights and wrongs by a money standard, is one cause, undoubtedly, of the disposition which is manifesting itself in this country to bring together all common-law and all equity powers of preventing wrong and enforcing right; as has been done, or attempted to be done in New York, by their last Revised Code; and as will, we think, be done in other States of this Union, in some form and in some measure. Indeed the recent legislation of England, by giving to the Common Law courts a kind of summary equity jurisdiction, seems to seek the same result. 506