When phenomena of this nature are related, the first hypothesis that occurs to the reader's mind is that of fraud. The medium is an impostor. His trick may be ingenious and carefully dissimulated, but it is certainly merely a trick. Therefore, in order to pursue these studies with any good results, this hypothesis must be disposed of once for all. Now this is not easy. Most men are so made that they have a high opinion of their own perspicuity, but a very unfavourable one generally of that of other men. They always believe that if they had been there they could have quickly discovered the imposture. Consequently, no precaution must be omitted; all safeguards must be employed, and it will be seen that the observers of Mrs Piper's phenomena have not neglected to do this. Professor James concealed the identity of as many as he could of the sitters whom he introduced to Mrs Piper. Personally, he was soon convinced that fraud had nothing to do with the phenomena. But the point was to convince others. It occured to a member of the Society for Psychical Research that it would be a good plan to cause Mrs Piper to be followed by detectives when she went out, and not only herself, but all the other members of her family. A singular idea, in my opinion. However, if detectives had not been employed, many people would even to-day believe that it would be possible to clear up the Piper mystery in a very short time, in the most natural way in the world. This is why Dr Hodgson, on his arrival in America, set detectives on the tracks of Mr and Mrs Piper. Absolutely nothing was discovered; Mr and Mrs Piper asked nobody indiscreet questions, made no suspicious journeys, did not visit cemeteries to read the names on graves. Finally, Mrs Piper, whose correspondence is at all times limited, received no letters from Intelligence Agencies. Later on, the method taken to make sure of her good faith was revealed to Mrs Piper. She was not at all offended; on the contrary, she saw how absolutely legitimate was the precaution. This is another proof of her uprightness and intelligence. Again, the idea that Mrs Piper could obtain the information she gives by means of inquiries made abroad is _a priori_ absurd to anyone who has studied the phenomena with any care. Her sitters, whom she received under assumed names, to the number of several hundreds, came from all points of the United States, from England, and even from other parts of Europe. The greater number passed through the hands of Professor James and Dr Hodgson, and all necessary precautions were taken that Mrs Piper should see them for the first time only a few moments before the commencement of the trance. Indeed, they were often only introduced after the trance had begun. These precautions have never injured the results. The sittings, at least those which were not spoilt by the medium's state of health, have always been marked by a large number of perfectly accurate details.