This section is from the book "Practical Lessons In Hypnotism", by Wm. Wesley Cook. Also available from Amazon: Practical Lessons In Hypnotism.
To successfully practice telepathy, the operator must possess a sound body and an evenly balanced mind, free from bad habits and at peace with all mankind. There must be no emotions or revengeful feelings to mar the tranquility of mind, and he must possess all the qualifications of a hypnotist described in Chapter II (Qualifications Of A Hypnotist).
Confidence of success is of the first importance, and this must be enhanced by the ability to make the mind passive and to concentrate the thought whenever desired. For experimentation it is always best to practice telepathy with some person was has been previously hypnotized by the operator, or who has given evidence of readily being mentally influenced. Also during the first experiments the subject, or recipient, as he is called in this connection, should not be far distant fr6m the operator, or transmitter.
If you have given the subject sufficient study and reflection to inspire confidence in your ability, secure a proper subject and give him the fullest understanding possible of what you desire to do. Select some one who is interested in the topic of telepathy and who is anxious to experiment.
Have the subject or recipient retire to an adjoining room and instruct him to make his mind perfectly passive; also inform him in a general way what is to be the character of your thoughts. For instance, state, "I am going to think of five geographical names," or, "I am going to think of four persons." After he has retired, concentrate your whole mind upon the names or persons you may select, and then will that the subject shall receive your thoughts. Do not be engrossed in a desire that he shall know what you are thinking about, for that desire implies a doubt, which is fatal, as it creates a new train of thought in your mind. Force upon yourself the felling that you are mentally expelling from your mind the thoughts selected, and that you are driving them into the recipients mind.
Your success in your first experiment will be demonstrated by the subject informing you of the words or persons selected. He may not be able at first to give you the actual words, but may tell you the substance of the thought. For instance, he may say, "You were thinking of a city in China. a river in Europe, one of the United States, one of the great lakes, and an island in the Pacific Ocean,"' or he may describe the persons that you selected. This may be due to the thoughts which the names called up to your own mind, for the bare name can scarcely be dwelt upon without qualification, unless it be in the case of figures.
After repeated experiments at close range, longdistance communications may be attempted, and they are just as easily and successfully performed when the thought of distance can be banished from the mind.
The author has performed very many most interesting experiments in telepathy with his friend, Mr. Erasmus Poole, a gentleman of high literary and scientific attainments, who has made the study of occult sciences an absorbing specialty.
Mr. Poole, a few years since, made a business trip to Boston, and it was agreed that an experiment at "double telepathy" should be attempted. In other words, that we should act as transmitter and recipient in turn. We agreed upon a day and hour and minute when we should place ourselves in communication. The author was first to transmit, and after a lapse of half an hour was to render his mind passive and receive. What was received in Boston was to be afterward sent by mail to Chicago, together with a written statement of what was sent, and a corresponding communication was to be mailed from Chicago to Boston. The following is the result:
"Boston, January 18th. - In my sitting to-day with you I received the following impressions, like a telegraphic message: 'Very cold; friend very sick; send black book.' "
The message transmitted by telepathy and afterward mailed to Chicago was: "Thermometer nine degrees below zero. Mr. Boettinger has typhoid fever. Please return the book on 'Psychology' you borrowed."
"Chicago, January 18th. - As agreed upon, I made myself passive, after sending you a message, and I received the following mental impressions: 'Time 4136. Smoke everywhere.' "
The actual message, as Mr. Poole afterward informed me by mail, was: "My watch number is 411366. Fire in my boarding house yesterday. Received a letter from Smith."
It is evident that the success of the experiment was quite satisfactory, and although the exact words were not received as transmitted, the thoughts were. In the first message the words "thermometer nine degrees below zero very naturally created the thought of "very cold." The appearance of the book on psychology created the thought of "black book," and the name and disease were absorbed in the thought of "friend very sick."

Rigidity of the body produced by catalepsy or profound hypnosis.
In the second message all the figures were received correctly, but the repetition of 1 and 6 were not comprehended. The words, "Fire in our boarding house yesterday" created the idea of smoke in the transmitter's mind, which was the thought received, and probably the smoke had made such an impression that the recollection of it precluded the concentration of thought upon the fact of receiving a letter from Smith, which slightly entertained thought was not received at all.
Enough has been learned and demonstrated in regard to telepathy to make it apparent that future generations may reach such a high degree of experience and knowledge regarding it, that it will be a recognized means of communication, just as wireless telegraphy, incomprehensible to most persons, and until lately regarded as impossible by all, has become practical in the sending of actual messages.
 
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