Apparitions and thought-transference: an examination of the evidence for telepathy. Frank Podmore

of the next four chapters, to examine this part of the evidence in detail, it will be well to consider its various defects and sources of error—defects common in some degree to all experiments of which living beings are the subject, and sources of error for the most part peculiar to this and kindred inquiries. The word experiment in this connection usually, and rightly, suggests the most perfect form of experiment, that in which all the conditions are known, and in which the results can be predicted both quantitatively and qualitatively. If, for instance, we add a certain quantity of nitric acid under given conditions to a certain quantity of benzine, we know that there will result a certain quantity of a third substance which is unlike either of its constituents in taste, smell, and physical properties. Or if we burn a given quantity of coal in a particular engine, we can predict, within narrow limits of error, the total amount of energy which will be evolved. That we cannot in the second instance predict with absolute accuracy the amount of energy produced is simply due to the difficulty of measuring with precision all the factors in the case. But when we leave the problems of chemistry and physics and approach the problems of biology, the difficulties increase a hundredfold. Here not only are we unable to measure the various factors, we cannot even name them. No skill or forethought would have enabled an observer, from however patient a study of parentage and environment, to have predicted the appearance, say, of Emanuel Swedenborg or Michael Faraday. Of the seven children of John Lamb and his wife it might have seemed easier to conjecture that the majority would not survive childhood, and that one would become insane, than that another should take his place amongst those whose writings the world would not willingly let die. And even where, as in most biological researches, the results drawn from observation can be to some extent checked and controlled by direct experiment, generations may elapse before the balance of probabilities on one side or the other becomes so great as to lead to unanimity amongst the inquirers. One of the most interesting, and certainly not the least important, of the questions now occupying biologists, is that of the transmission to the offspring of characters acquired in the lifetime of the individual. Observations have been accumulated on the subject since before the days of Lamarck; and these observations, interpreted and confirmed by experiment, have been adduced and are still held by many as evidence that such transmission occurs. On the other hand, Weismann and his followers contend that no such inference can legitimately be drawn from the observations and experiments quoted, and that the occurrence of such transmission is irreconcilable with what is known of the growth and development of the germ. And for all that has been said and written the opinion of competent biologists is still divided upon the question.

      But in many biological problems the conditions are much simpler, and the questions at issue can more readily be brought to the test of experiment. Yet even so various unknown factors are included, and the results obtained are correspondingly difficult of interpretation. No question affects us more nearly than the part played by the several kinds of food in repairing the daily waste of the human body. Statistics and analyses have been collected of workhouse, prison, and military dietaries; innumerable experiments have been conducted on fasting men and hypertrophied dogs and rabbits; and yet the precise function of nitrogenous substances in nutrition is still undetermined. Again, the import of the experiments made during the last few decades by Goltz, Hitzig, Ferrier, Horsley, and others on the functions of various areas of the brain substance, and the exact nature and degree of localisation which those experiments imply, are still matter of debate amongst the physiologists concerned.

      To take yet another instance, and one which has a more intimate bearing upon the experiments to be discussed. Some years ago Dr. Charlton Bastian claimed to have proved experimentally the fact of abiogenesis, or the generation of living organisms from non-living matter. He had placed various organic infusions in glass tubes, which were heated to the boiling point and then hermetically sealed. When the tubes were, after a certain interval, unsealed, the contained liquid was found in some cases to be swarming with bacteria. Believing that these micro-organisms and their germs were invariably destroyed by the heat of boiling water, Dr. Bastian saw no other conclusion than that the bacteria were formed directly from the infusion. His conclusions were not accepted by the scientific world. But they were rejected, not because the fact of abiogenesis was regarded as in itself improbable, nor yet because Dr. Bastian was unable to indicate by what steps or processes the transformation of an infusion of hay into living organisms of definite and relatively complex structure could be conceived to take place, but because Pasteur, Tyndall, and others showed that the germs of some of these micro-organisms are capable of sustaining for some minutes the heat of boiling water; and further, that when elaborate precautions were taken, by filtering and otherwise purifying the air, tubes containing similar infusions would remain sterile for an indefinite period.

      The conclusion that under certain conditions thought-transference may occur rests upon reasoning similar to that by which Dr. Bastian sought to establish a theory of abiogenesis. Neither the organs by which nor the medium through which the communication is made can be indicated; nor can we even, with a few trifling exceptions, point to the conditions which favour such communication. But ignorance on these points, though a defect, is not a defect which in the present state of experimental psychology can be held seriously to weaken the evidence, much less to invalidate the conclusion. That conclusion rests on the elimination of all other possible causes for the effect produced. But at this point the analogy between the two researches fails. Dr. Bastian's conjecture was based on a short series of experiments conducted by a single experimenter under one uniform set of conditions. At the first breath of criticism the whole fabric collapsed. The experiments here recorded represent the work of many observers in many countries, carried on with different subjects under a great variety of conditions. The results have been before the world for about twelve years, and during that period have been subjected to much adverse and some instructive criticism. But no alternative explanation which has yet been suggested has attained even a momentary plausibility.

      Whether the elimination of all other possible causes is indeed complete, or whether, as in Dr. Bastian's case, there may yet lurk in these experiments some hitherto unsuspected source of error, the reader will have the opportunity of judging for himself. To assist him in forming a judgment some of the main disturbing causes will be briefly indicated.

      (1) Fraud.—In nearly all the experiments referred to in this book the agent was himself concerned in the inquiry as a matter of scientific interest. But it necessarily happens on occasion that neither agent nor percipient are by education and position absolutely removed from suspicion of trickery in a matter where trickery might to imperfectly educated persons appear almost venial. If any such cases have been admitted, it is because the precautions taken appear to us to have been adequate. At the same time, the investigators of the Society for Psychical Research have come across some instances of fraud in cases where they had grounds for assuming good faith, and it may be useful, therefore, to illustrate some of the less obvious methods of acquiring intelligence fraudulently. The conditions of the experiment should of course, as far as possible, preclude, even where there is no ground for suspecting fraud, communication between the percipient and the agent, or any one else knowing the idea which it is sought to transfer.

      In the autumn of 1888 some experiments were conducted with a person named D., whose antecedents afforded, it was thought, justification for the belief that the claims which he put forward were genuine. D. acted as agent, the percipient being a subject of his own, a young woman called Miss N., who was apparently in a light hypnotic sleep during the experiment. It was soon discovered that the results were obtained by means of a code formed from a combination of Miss N.'s breathing with slight noises—a cough or the creak of a boot—made by D. himself. I have seen a somewhat similar code employed in Prince's Hall, Piccadilly, where the conjurer stood in the middle of the hall with a coin or other object in his hand, a description of which he communicated to his confederate on the platform by means of a series of breathings, deep enough visibly to move his dress-coat up and down on the surface of his white collar, punctuated by slight movements of head or hand. The novel feature in the first case, however, was that the percipient herself furnished the groundwork of the code, the punctuation alone being given by the conjurer. A still more elaborate form of collusion is described at length by Bonjean.[7] In this case the subject, a young woman named Lully, appears to have read the words to be conveyed after the fashion of a deaf mute, by the motion of the lips of the showman. Lully was apparently in a hypnotic trance, with the