At the beginning of this essay, I mentioned the attack made by Herr Pfungst. Herr Pfungst, the reader will remember, claims to prove that all the horse's replies are determined by imperceptible and probably unconscious movement on the part of the person putting the questions. This interpretation, which falls to the ground, like all the others, in the face of the actual facts, would not deserve serious discussion, were it not that the Berlin psychologist's report created an immense sensation some years ago and has succeeded in intimidating the greater part of the official German scientific world to this day. It is true that the report in question is a monument of useless pedantry, but we are none the less bound to admit that, such as it was, it annihilated poor Von Oaten, who, being no controversialist and not knowing how to proclaim the truth which was struggling for utterance, died in gloom and solitude. To make an end of this cumbrous and puerile theory, is it necessary to emphasize again that experiments in which the animal does not see the questioner are as regularly successful as the others? Krall, if you ask him, will stand behind the horse, will speak from the end of the room, will leave the stable altogether; and the results are just the same. They are the same again when the tests are made in the dark or when the animal's head is covered with a close-fitting hood. They do not vary either in the case of Berto, who is stone-blind, or when any other person whatever sets the problem in Krall's absence. Will it be maintained that this outsider or that stranger is acquainted beforehand with the imperceptible signs that are to dictate the solution which he himself often does not know? But what is the use of prolonging this fight against a cloud of smoke? None of it can bear examination; and it calls for a genuine effort of the will to set one's self seriously to refute such pitiful objections. 18 On the ground thus cleared and at the portal of this unlooked-for riddle, which comes to disturb our peace in a region which we thought to be finally explored and conquered, there are only two ways, if not of explaining, at least of contemplating the phenomenon: to admit purely and simply the almost human intelligence of the horse, or to have recourse to an as yet very vague and indefinite theory which, for lack of a better designation, we will call the mediumistic or subliminal theory and of which we will strive presently--and no doubt vainly--to dispel the grosser darkness. But, whatever interpretation we adopt, we are bound to recognize that it plunges us into a mystery which is equally profound and equally astonishing on either side, one directly related to the greatest mysteries that overwhelm us; and it is open to us to accept it with resignation or rejoicing, according as we prefer to live in a world wherein everything is within the reach of our intelligence or a world wherein everything is incomprehensible.