Unpleasant odors in a room may delay or entirely prevent the production of hypnosis. Tobacco smoke is especially antagonistic to those not accustomed to it, and even after such subjects have been hypnotized they are liable to awaken or become unmanageable, when someone near them commences to smoke. Under such circumstances, if the operator realizes the cause of the disturbance, he should make some such suggestion to the subject as, "Can you smell that delightful incense burning? It is a delightful odor." These words will be sufficient to at once overcome the physical discomfort caused by the smoke.

An operator, especially a beginner, must be continually on the alert to avoid anything and everything that might possibly interfere with his success. For instance, remember that people do not like to detect the odor of onions or garlic on the breath of others. Never eat such articles if you intend to hypnotize subjects. The disagreeable sensation caused by the odor may overcome your hypnotic influence or render it difficult to place them under control. While the sensation can be overcome by suggestion if the subject is disturbed by it while under control, suggestion is of no avail before hypnosis is produced.

As disagreeable odors are detrimental to hypnotic control, so agreeable or pleasant odors are excellent auxiliaries in producing hypnosis. Strong, sweet odors are especially useful. Perfume sprinkled about the room will aid the operator, and the presence of fragrant blooming flowers will always be found useful. The heliotrope is one of the best plants in this connection, and a number of them in the operating room will give a heavy, sweet odor, profound enough to be agreeably oppressive, and in a measure tranquillize the tendency to nervous irritability so often experienced by persons subjecting themselves to hypnotic influences for the first time. Lilacs and tuberoses are equally as useful as the heliotrope. Many persons cannot at any time inhale the odors from these flowers without being soothed and rendered drowsy, especially when in an atmosphere of quietude or solemnity.