Our own generation has got rid of these erroneous juridical theories， partly by outgrowing the intellectual state to which they belong， and partly by almost ceasing to theorise on such subjects altogether. The favourite occupation of active minds at the present moment， and the one which answers to the speculations of our forefathers on the origin of the social state， is the analysis of society as it exists and moves before our eyes； but， through omitting to call in the assistance of history， this analysis too often degenerates into an idle exercise of curiosity， and is especially apt to incapacitate the inquirer for comprehending states of society which differ considerably from that to which he is accustomed. The mistake of judging the men of other periods by the morality of our own day has its parallel in the mistake of supposing that every wheel and bolt in the modern social machine had its counterpart in more rudimentary societies. Such impressions ramify very widely， and masque themselves very subtly， in historical works written in the modern fashion； but I find the trace of their presence in the domain of jurisprudence in the praise which is frequently bestowed on the little apologue of Montesquieu concerning the Troglodytes， inserted in the Lettres Persanes.
Neither Ancient Law nor any other source of evidence discloses to us society entirely destitute of the conception of Contract. But the conception， when it first shows itself， is obviously rudimentary. No trustworthy primitive record can be read without perceiving that the habit of mind which induces us to make good a promise is as yet imperfectly developed， and that acts of flagrant perfidy are often mentioned without blame and sometimes described with approbation. In the Homeric literature， for instance， the deceitful cunning of Ulysses appears as a virtue of the same rank with the prudence of Nestor， the constancy of Hector， and the gallantry of Achilles. Ancient law is still more suggestive of the distance which separates the crude form of Contract from its maturity. At first， nothing is seen like the interposition of law to compel the performance of a promise. That which the law arms with its sanctions is not a promise， but a promise accompanied with a solemn ceremonial. Not only are formalities of equal importance with the promise itself， but they are， if anything， of greater importance； for that delicate analysis which mature jurisprudence applies to the conditions of mind under which a particular verbal assent is given appears， in ancient law， to be transferred to the words and gestures of the accompanying performance.
No pledge is enforced if a single form be omitted or misplaced， but， on the other hand， if the forms can be shown to have been accurately proceeded with， it is of no avail to plead that the promise was made under duress or deception. The transmutation of this ancient view into the familiar notion of a Contract is plainly seen in the history of jurisprudence. First one or two steps in the ceremonial are dispensed with； then the others are simplified or permitted to be neglected on certain conditions； lastly， a few specific contracts are separated from the rest and allowed to be entered into without form， the selected contracts being those on which the activity and energy of social intercourse depends. Slowly， but most distinctly， the mental engagement isolates itself amid the technicalities， and gradually becomes the sole ingredient on which the interest of the jurisconsult is concentrated. Such a mental engagement， signified through external acts， the Romans called a Pact or Convention； and when the Convention has once been conceived as the nucleus of a Contract， it soon becomes the tendency of advancing jurisprudence to break away the external shell of form and ceremony. Forms are thenceforward only retained so far as they are guarantees of authenticity， and securities for caution and deliberation. The idea of a Contract is fully developed， or， to employ the Roman phrase， Contracts are absorbed in Pacts.
The history of this course of change in Roman law is exceedingly instructive. At the earliest dawn of the jurisprudence， the term in use for a Contract was one which is very familiar to the students of historical Latinity. It was nexum， and the parties to the contract were said to be nexi， expressions which must be carefully attended to on account of the singular durableness of the metaphor on which they are founded. The notion that persons under a contractual engagement are connected together by a strong bond or chain， continued till the last to influence the Roman jurisprudence of Contract； and flowing thence it has mixed itself with modern ideas. What then was involved in this nexum or bond？ A definition which has descended to us from one of the Latin antiquarians describes nexum as omne quod geritur per aes et libram， "every transaction with the copper and the balance，" and these words have occasioned a good deal of perplexity. The copper and the balance are the well-known accompaniments of the Mancipation， the ancient solemnity described in a former chapter， by which the right of ownership in the highest form of Roman Property was transferred from one person to another. Mancipation was a conveyance， and hence has arisen the difficulty， for the definition thus cited appears to confound Contracts and Conveyances， which in the philosophy of jurisprudence are not simply kept apart， but are actually opposed to each other. The jus in re， right in rem， right "availing against all the world，" or Proprietary Right， is sharply distinguished by the analyst of mature jurisprudence from the jus ad rem， right in personam， right "availing a single individual or group，" or obligation. Now Conveyances transfer Proprietary Rights， Contracts create Obligations —— how then can the two be included under the same name or same general conception？ This， like many similar embarrassments， has been occasioned by the error of ascribing to the mental condition of an unformed society a faculty which pre-eminently belongs to an advanced stage of intellectual development， the faculty of distinguishing in speculation ideas which are blended in practice. We have indications not to be mistaken of a state of social affairs in which Conveyances and Contracts were practically confounded； nor did the discrepance of the conceptions become perceptible till men had begun to adopt a distinct practice in contracting and conveying.
It may here be observed that we know enough of ancient Roman law to give some idea of the mode of transformation followed by legal conceptions and by legal phraseology in the infancy of Jurisprudence. The change which they undergo appear to be a change from general to special； or， as we might otherwise express it， the ancient conceptions and the ancient terms are subjected to a process of gradual specialisation. An ancient legal conception corresponds not to one but to several modern conceptions. An ancient technical expression serves to indicate a variety of things which in modern law have separate names allotted to them. If however we take up the history of Jurisprudence at the next stage， we find that the subordinate conceptions have gradually disengaged themselves and that the old general names are giving way to special appellations. The old general conception is not obliterated， but it has ceased to cover more than one or a few of the notions which it first included. So too the old technical name remains， but it discharges only one of the functions which it once performed. We may exemplify this phenomenon in various ways.
Patriarchal Power of all sorts appears， for instance， to have been once conceived as identical in character， and it was doubtless distinguished by one name. The Power exercised by the ancestor was the same whether it was exercised over the family or the material property —— over flocks， herds， slaves， children， or wife. We cannot be absolutely certain of its old Roman name， but there is very strong reason for believing， from the number of expressions indicating shades of the notion of power into which the word manus enter， that the ancient general term was manus. But， when Roman law has advanced a little， both the name and the idea have become specialised. Power is discriminated， both in word and in conception， according to the object over which it is exerted. Exercised over material commodities or slaves， it has become dominium —— over children， it is Potestas —— over free persons whose services have been made away to another by their own ancestor， it is mancipium —— over a wife， it is still manus.
The old word， it will be perceived， has not altogether fallen into desuetude， but is confined to one very special exercise of the authority it had formerly denoted. This example will enable us to comprehend the nature of the historical alliance between Contracts and Conveyances. There seems to have been one solemn ceremonial at first for all solemn transactions， and its name at Rome appears to have been nexum. Precisely the same forms which were in use when a conveyance of property was effected seem to have been employed in the making of a contract. But we have not very far to move onwards before we come to a period at which the notion of a Contract has disengaged itself from the notion of a Conveyance. A double change has thus taken place. The transaction "with the copper and the balance，" when intended to have for its office the transfer of property， is known by the new and special name of Mancipation. The ancient Nexum still designates the same ceremony， but only when it is employed for the special purpose of solemnising a contract.
责任编辑：wangpeng6151
