One day when I was a junior medical student, a very important Boston surgeon visited the school and delivered a great treatise on a large number of patients who had undergone successful operations for vascular reconstruction. At the end of the lecture, a young student at the back of the room timidly asked, "Do you have any controls?" Well the great surgeon drew himself up to his full height, hit the desk, and said, "Do you mean did I not operate on half of the patients?" The hall grew very quiet then. The voice at the back of the room hesitantly replied, "Yes, that's what I had in mind." Then the visitor's fist really came down as he thundered, "Of course not. That would have doomed half of them to their death!" God, it was quiet then, and one could scarcely hear the small voice ask, "Which half?"
As soon as Te Shan crossed the threshold he said, "Long have I heard of Lung T'an (Dragon Pond), but now that I've arrived here, there's no pond to see and no dragon appears." Master Lung T'an came out from behind a screen and said, "You have really arrived at Lung T'an." Te Shan bowed and withdrew.
During the night, Te Shan entered Lung T'an's room and stood in attendance till late at night. Lung T'an said, "Why don't you go?" Te Shan bade farewell, lifted up the curtain, and went out; he saw that it was dark outside, so he turned around and said, "It's dark outside." Lung T'an lit a paper lantern and handed it to Te Shan; as soon as Te Shan took it, Lung T'an blew it out. Te Shan was vastly and greatly enlightened.