* terms of the contract at their pleasure by a special agree ment. So a mandatary may impose upon himself an additional degree *of liability by his interfering with the property committed to his charge, by which its custody is rendered more insecure. (m) So it may be gathered from the cases, and from obvious reasons, that where the work to be done requires peculiar skill and care, and the mandatary undertakes it in such way as to be bound to go through with it, the want of the required skill and care would be negligence enough. (n) issory note was delivered to the defendant, on his voluntarily undertaking, without reward, "to secure and take care of it,"it was held, that he was not bound to take any active measures to obtain security, but was simply bound to keep the note carefully and securely, and receive the money due thereon when offered. Shaw, C. J., remarked: "The term, to 'secure,' may be deemed ambiguous, meaning either to obtain security, or to keep securely; but associated with, the words 'take care of,' and being a gratuitous undertaking, we do not understand that the defendant was to take active measures to obtain security, but simply to keep the note carefully and securely, and receive the money due thereon, when offered. This last authority and duty would seem to result from the custody of the note. . . . The law has endeavored to make a distinction in the degrees of care and diligence to which different bailees are bound; distinguishing between gross negligence, ordinary negligence, and slight negligence; though it is often difficult to mark the line where the one ends and the other begins. And it must be often left to the jury, upon the nature of the subject-matter, and the particular circumstances of each case, with suitable remarks by the judge, to say whether the particular case is within the one or the other." See also Mechanics and Traders Bank v. Gordon, 5 La. An. 604.

(m) Nelson v. Macintosh, 1 Stark. 287; Bradish v. Henderson, 1 Dane, Abr. 810.

(n) See the remarks of Lord Lough-borough in the case of Shiells v. Black-burne, quoted ante, p. *104, note (l). Mr. Justice Heath, in the same case, said: "If a man applies to a surgeon to attend him in a disorder, for a reward, and the surgeon treats him improperly, there is gross negligence, and the surgeon is liable to an action; the surgeon would also be liable for such negligence, if he undertook gratis to attend a sick person, because his situation implies skill in surgery; but if the patient applies to a man of a different employment or occupation, for his gratuitous assistance, who either does not exert all his skill, or administers improper remedies to the best of his ability, such person is not liable." But even a mandatary, whose occupation implies peculiar skill, is not required to exercise the greatest amount of skill; if he exercises such skill as is usually exercised by members of his profession, it is sufficient The law upon this subject is admirably stated by Mr. Justice Porter, in the case of Percy v. Millaudon, 20 Mart. (La.) 68, 76. His language was as follows: "It is said by a writer of great authority [Po-thier], who treats of the doctrine of mandate, that the mandatary cannot excuse himself by alleging a want of ability to discharge the trust undertaken. That it will not be sufficient for him to say he acted to the best of his ability, because he should have formed a more just estimate of his own capacity before he engaged himself. That, if he had not agreed to become the agent, the principal could have found some other person willing and capable of transacting the business correctly. This doctrine, if sound, would make the attorney in fact responsible for every error in judgment, no matter what care and attention he exercised in forming his opinion. It would make him liable to the principal in all doubtful cases, where the wisdom or legality of one or more alternatives was presented for his consideration, no matter how difficult the subject was. And if the embarrassment, in the choice of measures, grew out of the legal difficulty, it would require from him knowledge and learning, which the law only presumes to those who have made the jurisprudence of their country the study of their lives, and which knowledge often fails in them from the intrinsic difficulty of the subject, and the fallibility of human judgment It is no doubt true,

So if he enters upon the * undertaking, it is said that he must obey instructions, or be liable for his departure. (o) Indeed, it would be in that case gross negligence. But it might be otherwise, if the owner had no reason to believe that the mandatary possessed skill sufficient for the precise purpose for which he was employed; and certainly would be, if he had good reason to know that he had not the skill; as if he gave a valuable watch to be repaired, to one whom he knew was not a watchmaker; or to one who, although a watchmaker, was known by him to be unaccustomed to watches of that kind. All these differences rest upon the ground of the presumed intention of the parties. And on the same principle, although the subject-matter of the mandate do not necessarily imply superior skill in the mandatary, still, if he is known to possess superior skill he is bound to exercise it. (p) that if the business to be transacted presupposes the exercise of a peculiar kind of knowledge, a person who would accept the office of mandatary, totally ignorant of the subject, could not excuse himself on the ground that he discharged his trust with fidelity and care. A lawyer who would undertake to perform the duties of a physician; a physician who would become an agent to carry on a suit in a court of justice; a bricklayer who would propose to repair a ship, or a landsman who would embark on board a vessel to navigate her, may be presented as examples to illustrate this distinction. But when the person who is appointed attorney in fact has the qualifications necessary for the discharge of the ordinary duties of the trust imposed, we are of opinion that on the occurrence of difficulties in the exercise of it, which offer only a choice of measures, the adoption of a course from which loss ensues cannot make the agent responsible, if the error was one into which a prudent man might have fallen. The contrary doctrine seems to us, to suppose the possession, and require the exercise, of perfect wisdom in fallible beings. No man would undertake to render a service to another on such severe conditions. The reason given for the rule, namely, that if the mandatary had not accepted the office, a person capable of discharging the duty correctly would have been found, is quite unsatisfactory. The person who would have accepted, no matter who he might be, must have shared, in common with him who did, the imperfection of our nature; and consequently must be presumed just as liable to have mistaken the correct course. The test of responsibility, therefore, should be, not the certainty of wisdom in others, but the possession of ordinary knowledge; and by showing that the error of the agent is of so gross a kind, that a man of common sense and ordinary attention would not have fallen into it The rule which fixes responsibility, because men of unerring sagacity are supposed to exist, and would have been found by the principal, appears to us essentially erroneous." '