_Occult Influences Should be Considered by Lawyers and Judges._—In this connection it should be borne in mind by lawyers and judges, that in the case of a physician treating disease, or a surgeon repairing an injury, occult influences frequently play a most important part. Professor Elwell in his work on Malpractice, etc., p. 25, lays great stress on this element of uncertainty. He says: “In the case of physicians, surgeons, attorneys, etc., another and important element besides skill enters into the result, and for this reason the degree of responsibility is to a certain extent and in a manner indicated and influenced. This important element is the operation of causes and influences over which the practitioner has but little or no control. They are occult, and no human foresight is able to anticipate them before they have completely deranged and materially interfered with his plans by bringing about a different result than that confidently depended upon.”[197] _Change and Advancement in Medical Knowledge also to be Considered._—It should on the other hand be clearly understood that the constant change and improvement which are going on in medical and surgical education, in the discovery of new remedies and new methods of treatment, and in the invention of new instruments, tend constantly to elevate the average skill and intelligence of the profession, and with them the standard by which the courts will determine liability for negligence. What would have been, but a few years ago, fully recognized by the courts as ordinary skill in the treatment of disease and the performance of operations, would now be regarded as antiquated and less than ordinary skill, because of the advancement in the knowledge of means which can be devoted to the treatment of disease and injury.[198] We have already seen that what is the degree of skill to be required of one practising in a small town or a country district sparsely inhabited, and what is required in the case of a city practitioner, may differ to some extent with the circumstances. Quacks and pretenders, however, must be judged by the standard of regular practitioners.[199]