No doubt the plaintiff's legal advisers hardly expected that the consequence of submitting their client to medical examination would be that the specialist by whom he was examined would give evidence of a crucial admission going to the cause of action. Had this been anticipated doubtless they would have been reluctant to allow their client to go unattended. On the other hand it seems equally clear that the purpose of the medical examination was to enable the defendant commissioner to see for himself what the plaintiff's injuries were and what was his present condition as the result of the accident. It can hardly be doubted that both parties understood that, if, as in the event happened, the negotiations for settlement should break down, then Dr. Teece might give the evidence of his actual observations of the plaintiff's bodily condition and the opinion he formed of his injuries. In this sense the examination had a double aspect. Primarily it was to enable the defendant to obtain a medical report in order to form an estimate of his injuries for the purpose of making an offer of settlement. Failing settlement, the purpose was to enable the defendant's medical expert to give evidence of what he saw. The law relating to communications without prejudice is of course familiar. As a matter of policy the law has long excluded from evidence admissions by words or conduct made by parties in the course of negotiations to settle litigation. The purpose is to enable parties engaged in an attempt to compromise litigation to communicate with one another freely and without the embarrassment which the liability of their communications to be put in evidence subsequently might impose upon them. The law relieves them of this embarrassment so that their negotiations to avoid litigation or to settle it may go on unhampered. This form of privilege, however, is directed against the admission in evidence of express or implied admissions. It covers admissions by words or conduct. For example, neither party can use the readiness of the other to negotiate as an implied admission. It is not concerned with objective facts which may be ascertained during the course of negotiations. These may be proved by direct evidence. But it is concerned with the use of the negotiations or what is said in the course of them as evidence by way of admission. For some centuries almost it has been recognised that parties may properly give definition to the occasions when they are communicating in this manner by the use of the words "without prejudice" and to some extent the area of protection may be enlarged by the tacit acceptance by one side of the use by the other side of these words: see Thomas v. Austen [1] ; Kurtz & Co. v. Spence & Sons [2] ; Paddock v. Forrester [3] ; Hoghton v. Hoghton [4] ; In re River Steamer Co.; Mitchell's Claim [5] ; Walker v. Wilsher [6] . Needless to say, the privilege is a matter to be raised by objection to the admissibility of the evidence. For the purpose of deciding such an objection the judge may take evidence on the voir dire. The problem in the present case is whether what according to Dr. Teece the plaintiff said to him as to the manner in which the accident occurred is within the protection of the privilege. Looked at antecedently the question may be stated as being whether what he might unexpectedly say to Dr. Teece should be regarded as within the area of protection. In the first place as a matter of ordinary knowledge it must have been within the contemplation of the parties that some statement would be made by the plaintiff to Dr. Teece concerning the nature of his injuries. It could hardly be expected that an orthopaedic surgeon would not ask questions about symptoms, pain, capacity to move and so forth, and such matters must have formed part of the material upon which Dr. Teece would form his opinion. Clearly enough, these were not matters which were considered by the parties to fall within the protection of without prejudice negotiations. For it is plain that Dr. Teece was expected to give evidence of the opinion he formed should the negotiations for settlement break down. The question, however, does not depend altogether upon the expectations of the parties. It depends upon what formed part of the negotiations for the settlement of the action and what was reasonably incidental thereto. On the one hand it is contended that it was reasonably incidental to the negotiations to place the plaintiff without reserve in the hands of Dr. Teece and allow him to talk freely. On the other hand it is pointed out that Dr. Teece's function was wholly medical, that no one anticipated the plaintiff discussing the cause of action with him, that he had no function to perform in relation to the settlement except to report his medical judgment of the plaintiff's condition, past, present and future, and that he was not a general agent of the defendant but was appointed only ad hoc to make a medical examination. Further, for purposes of the medical examination it was not necessary or reasonable that the plaintiff should state anything touching his cause of action.