It is now almost thirty years since Dr. Burq first observed the favourable effect produced by the external application of different metals on patients suffering from various forms of anæsthesia. Burq remarked that the same effect was not produced by the same metal in all cases, but that the therapeutic success was due in one case to gold and in another to iron. This fact led him to assume that, in cases where one metal proved beneficial when applied to the skin, still better results might be obtained by giving this patient a preparation of the metal that suited him for internal use, and thus promoting a constitutional action. But even his first assertions met with a cold reception, and his later assertions of the success obtained by internal use of the metals received quite emphatic denial from the profession, so that the whole question fell into discredit. Nothing daunted by this, and fully convinced of the accuracy of his observations, Burq applied to the Société de Biologie in Paris, to appoint a committee to test his assertions impartially, and report on the results of their investigations. A committee, consisting of MM. Charcot, Luys and Dumontpallier, was appointed, and on the 14th of April, 1877, M. Dumontpallier, as speaker, delivered the following report:—