hypothesis excepting their own, the authority of even the whole body of such persons is of no more account than that of any other class of intelligent and cultivated men. In the ages when ecclesiastical authority exercised great power over the beliefs of men upon questions of physical science, the superiority was accorded to the authority which claimed it, and the scientist who propounded a new physical theory that did not suit the theologian was overborne. It seems to me that it is a tendency of the present age to substitute the authority of scientific experts in the place of the ecclesiastical authority of former periods, by demanding that something more than the office of witnesses of facts shall be accorded to them. We are told that it is a very important proof of the soundness of deductions, that the deductions are drawn by the greater number of the specialists who have examined the facts. Sometimes this is carried so far as to imply presumption in those who do not yield assent to the theory, as if it ought to be accepted upon the authority of the experts whose proper office it is to furnish us with the facts, and whose deductions we have to examine upon the strength of their reasoning. Those of us who are not professors of the particular science may be charged with ignorance or incapacity if we do not join in the current of scientific opinion. But, after all, the new theory challenges our belief. If we examine it at all, we must judge of it, not by the numbers of those who propound or accept it, or by any amount of mere authority, but by the soundness of the reasoning by which its professors support it.