would never have been discussed, even for a moment, in any scientific body.
The three methods of deceiving the subject by which alone the element of error from mind acting on body can be eliminated, and the results of experiments with living human beings transferred from the realm of opinion to science or positive knowledge, are these:
1. By doing something when the subject experimented on believes that we are doing nothing.
2. By doing nothing when the subject believes that we are doing something.
3. By doing something different from what the subject believes is being done.
In experiments of importance, as where radical and overwhelming discoveries in science are claimed to be made, all of these methods of deceiving should be used; and it is because they are not used in the experiments of scientific men that we are constantly compelled to face and listen to the claims of "animal magnetism," of "odic force" of "spiritism," of "cundurango," of "blue glass," and, during the past year, of "Mollie Fancher," of "metalloscopy," and "metal-therapeutics."
A classical example of one method of deception in experiments of this character was afforded by the exposé of the performances of mesmerized or professedly mesmerized girls by Mr. Wakley, of the London "Lancet." A good example of neglect of this deception, as well as of ignorance of the relation of mind to body, is found in the experiments of Dr. Vansant with magnets, as published by him a few years ago. This writer gives an immense number of differential symptoms that, as he claims, are produced by the north and south poles of the magnet; his experiments were in the same line with the famous Perkins tractors, though apparently more scientific; the same criticism applies to the researches that are now being made in the Salpêtrière Hospital in Paris, where, according to the testimony of experts who have witnessed them, and the statements of the experimenters themselves, no systematic deception is employed or even suggested.
That even the strongest leaders in physiology are not fully armed against the errors that beset experimental research, when living human beings are the subjects, is shown in the not long ago published Lowell Lectures of Professor Brown-Séquard, wherein that master in experimental study through the processes of vivisection declares that the claims of telling of time through the back of the head are authentic. Deductive reasoning for ever disproves this claim, which any inductive research, properly conducted, must always confirm; but any test to be of value must, at every step, shut out absolutely all the six avenues of error; and the report of any test, in order to be worth reading, must clearly state and show that all such errors were so excluded.
