The Bright Messenger by Algernon Blackwood

To Devonham, meanwhile, LeVallon's behaviour was polite and kind and distant; he did not show distrust of any sort, but he betrayed a certain diffidence, reserve and caution. Trust he felt; sympathy he did not feel. To the amusement of Fillery, he suggested almost a kind of mild contempt when dealing with him, and this amusement was increased by the fact that it obviously annoyed Devonham, while it gratified his chief. For towards Fillery, LeVallon behaved with an intimate and understanding sympathy that proved his instantaneous affection based upon mutual comprehension. It seemed that LeVallon and Fillery had known one another always.

It was doubtless, due to this innate sympathy between them that Edward Fillery's rare gift of absorbing the content of another's mind, even to the point of taking on that other's conditions, physical and emotional at the same time, was so successful. By means of a highly developed power of auto-suggestion, he had learned so to identify his own mind, thought, feeling with those of a patient, that there resulted a kind of merging by which he literally became that patient. He felt with him. As a subject sees the pictures in the hypnotiser's mind, perceives his thoughts, divines his slightest will, so Fillery, reversing the process, could realize for the moment exactly what his patient was thinking, feeling, desiring. It was of great use to him in his strange practice.