The development of law, therefore, whether unwritten or written, is primarily the work of the lawyer. It is the adoption by the judge of what is proposed at the bar.[Footnote: See Chap. VI, X.] There are obvious limits to this power of developing unwritten law. The courts are not to push forward into a place more appropriate for the legislature to occupy. Mr. Justice Holmes of the Supreme Court of the United States, when Chief Justice of Massachusetts, stated with his usual elegance and force the bounds within which, as it seemed to him, judicial authority should be kept. In a common law suit against a railroad company for damages suffered by an accident on its road, the defendant had asked the trial court to order the plaintiff to submit to an examination of his person by a physician whom it named, for the purpose of determining what injuries he had really suffered. "We agree," said the Chief Justice, "that in view of the great increase of actions for personal injuries it may be desirable that the courts should have the power in dispute. We appreciate the ease with which, if we were careless or ignorant of precedent, we might deem it enlightened to assume that power. We do not forget the continuous process of developing the law that goes on through the courts in the form of deduction or deny that in a clear case it might be possible even to break away from a line of decisions in favor of some rule generally admitted to be based upon a deeper insight into the present wants of society. But the improvements made by the courts are made, almost invariably, by very slow degrees and by very short steps. Their general duty is not to change, but to work out, the principles already sanctioned by the practice of the past. No one supposes that a judge is at liberty to decide with sole reference even to his strongest convictions of policy and right. His duty in general is to develop the principles which he finds with such consistency as he may be able to attain.... In the present case we perceive no such pressing need of our anticipating the legislature as to justify our departure from what we cannot doubt is the settled tradition of the common law to a point beyond that which we believe to have been reached by equity, and beyond any to which our statutes dealing with kindred subjects ever have seen fit to go. It will be seen that we put our decision, not upon the impolicy of admitting such a power, but on the ground that it would be too great a step of judicial legislation to be justified by the necessities of the case."[Footnote: Stack _v._ New York, New Haven and Hartford Railroad Co., 177 Massachusetts Reports, 155; 58 Northeastern Reporter, 686.]