Psychiques (1909-12), and confirmed by Dr. von Schrenck- Notzing in 1913-4. Some of the photographs appeared to give a clew to the mechanics of these phenomena by showing very fine threads connecting the hands of the medium and passing beneath the object levitated. It is argued however, partly on the strength of the negative results of investigating the medium before and after the phenomena, partly on the ground of differences in the appearance of these threads and of cotton, silk and hair (il- lustrated), that the threads were of a psychic and supernormal character, and in fact plastic emanations similar to those of " Eva C." In the summer of 1914 the medium came to London to be examined by the S.P.R., but the outbreak of war prevented the continuation of the investigation.
Another branch of physical phenomena is represented by what is called " spirit-photography." In this, as in the (now extinct) method of " slate- writing," everything depends on the prevention of fraudulent substitutions in the plates (or slates). If this is neglected, the production of " spirit-photographs " becomes easy enough. One of the earliest practitioners of this art, William Keeler, has recently suffered annihilating exposure of his " Lee-Bocock " frauds at the hands of Dr. W. F. Prince (Am. S.P.R. Proceedings, vol. xiii. 2, March 1920), after having had his case stated in Proceedings, vol. viii. (1913), of the same society. Other cases of " spirit-photography " may be said to be still under investigation, and, though none had in 1921 been proved genuine, their detection is usually a highly technical matter. Dr. Prince has also convincingly shown by a critical study of the evidence that an old " poltergeist " case, " the Great Amherst Mystery " (1879), was in all probability due to the (unconscious) fraud of the medium, who had been " dissociated " by a shocking event in her personal history, which she had, apparently, " re- pressed" (Am. S.P.R. Proceedings, vol. xiii. i, 1919).
" Dowsing," as a method of finding water in dry places, con- tinues to be used with considerable success, and it is certainly impressive to find that certain firms of well-sinkers regularly employ dowsers, and are so confident about their skill that they are willing to make contracts on " no find, no pay " terms. It is said, however, that they then (not unreasonably) protect them- selves by charging higher rates. The subject was somewhat actively debated in Germany shortly before the World War, because the German governor of South-West Africa had a cousin who was a water-finder, and employed him with great success (cf. Des Landral von Uslars Arbeiten mil dcr Wiinschelrute in Siidwesl Afrika, Stuttgart, 1912). A pamphlet by A. J. Ellis, issued by the U.S. Geological Survey (The Divining Rod, Washington, 1917), though it dismisses the matter dogmatically as a mere superstition, has a useful bibliography.
Thinking Animals. Before the World War Germany was also the chief home of a vigorous dispute about "thinking animals," which must be noticed in this connexion, not only because allega- tions of supernormal faculty were made, but because the logical problems involved, the difficulties in ascertaining the facts and in guarding against deception, and the partisanship of the dis- putants, were identical. For though at first the issue appeared to be simply a question of zoological fact, to be decided experi- mentally by biological and psychological experts, it soon appeared that not only was there the usual divergence between con- servatives and progressives, but that the experts were divided by the conflict between the tendencies to emphasize the unity of life and to affirm the supremacy of the human mind; moreover, when, as was soon the case, a considerable amount of odium theo- logicum was imported into the discussion, a similar division was observable among theologians. The result was a complete replica of a controversy in psychical research. The trouble began so long ago as 1904, when Herr von Osten produced a horse, his " Clever Hans," which he had taught to do simple sums by tapping with his hoofs. He had proceeded on the logically false assumption that mathematical thought is pecu- liarly arduous, and on the biologically false assumption that to discover unsuspected extensions of animal intelligence would be particularly cogent in directions remote from the natural interests of the beast. However, " Hans " indisputably tapped
out the right responses in the presence of his master, and even (though rarely) in his absence, and the scientific scandal became so great that an inquiry had to be made (by order of the Ministry of Education) ; as a result the explanation was adopted, with the approval of the Berlin psychologist, Prof. Stumpf, that the observant animal reacted to slight, unconscious indications given by the experimenter. Thus there was neither thought nor fraud, but only visual hyperaesthesia (cf. Pfungst, Clever Hans, English translation, New York, 1911).
Officially this report was supposed to settle the matter. But an Elberfeld gentleman named Krall was not satisfied. He bought " Clever Hans " after von Osten's death, and examined his visual acuity, finding it to be 25 times that of a man. He also trained up a whole stud of equine mathematicians, that became famous as " the Elberfeld horses." Among them one turned out to be a genius, " Muhamed," while another, " Berto," was blind, and so incapable of visual hyperaesthesia. Elberfeld became a place of pilgrimage; a multitude of books, pamphlets and articles appeared (cf. Krall, Denkende Tiere, Leipzig, 1912); a review was founded for the recording of the prodigies of animal thought (Tierseele, 1913). Presently, at Mannheim, an invalid lady took to exhibiting a thinking dog, " Rolf," who, though not so mathematically minded, appeared to be gifted with a rare sense both of philosophy and humour. True, the animal refused to " work " unless held by a chain, and this procedure naturally fostered suspicions that the natural brilliance of his mind might have been improved by a little judicious wire-pulling; but there arose plenty of reputable observers to testify that the chain was kept slack, and even some to declare that " Rolf " had been known to answer correctly in the absence of his owner and had furnished answers not known to any human mind: the opposi- tion, therefore, could only attack the competence of the observers, and sometimes succeeded in showing that they had been laxer than they had imagined. Yet, despite the indignant protests of those who claimed to have vestiges of common sense or knowl- edge a priori of where the limits of the possible were laid down, the open-minded (like Darwin), not afraid of " fool " experi- ments, went to see, and were duly puzzled: even eminent psychologists, like Prof. Claparede of Geneva, reported favour- ably, more or less. A poet, Maeterlinck, came away from the horses with the conviction that the phenomena were super- normal; and was satisfied that horses, dogs and cats were by nature " psychics," while elephants, monkeys and asses were not and, unlike the former, could not tap the cosmic reservoir of potential knowledge. The said " reservoir " was hypothetical, but seemed to be needed to provide for the correctness of answers not known to any human mind, and so transcending " telepathy " (which had also been suggested) (cf. The Unknown Guest, Eng. trans., T9i4, p. 267).
Clearly, this question of "thinking animals" exhibits the tantalizing perversity of other problems in psychical research. The truth about it is not a problem in pure science, and is not susceptible of settlement by its methods. For these demand that the good faith of the observers can be presupposed and that undistorted observation of the facts is possible, both conditions often far less completely fulfilled, even in the established sciences, than is usually assumed. In the unreclaimed borderland between superstition and science neither condition can be satisfied; every " fact " may prove to be real only as a hallucination is real, or to be distorted into a monstrous mirage by prejudice and bias, while the will to believe (and equally the will to disbelieve) is so free to select, to emphasize, to interpret, that it can create practically any " fact " it chooses. In short, truth in this region is unmistakably emotional; men's attitude towards it essentially resembles their attitude in religion or in politics; the abstraction from human feeling (or rather from every feeling but the desire for knowledge), which is postulated in the ideal of pure reason, is simply impracticable here. So long as every " fact " adduced on either side has to be treated as suspect, and every step is con- tentious, scientific progress, if it is possible at all, cannot be otherwise than slow. There is only one way for believers in the .supernormal to shortcircuit this procedure: if they can apply
