"That may be so--no doubt it is so," I returned doggedly--"but there has been too much foul play in this hidden treasure hunt, as witness that murder in Whitehall Court, to content me or to let me take as gospel everything you choose to tell me and to treat as wisdom everything you like to leave untold. I must insist on my rights as an individual in this matter before we go any further or any deeper into mutual obligations which later all of us may find it difficult to free ourselves from, however much we may desire to do so. To-day I am my own master--I can stay or I can go. My decision now will rest on one consideration alone. What is this Order of St Bruno?" "I cannot tell you," said the Prior, and his strong face looked out at me without one shadow of hesitancy or fear. "Casteno," I went on, turning to the Spaniard, "you are in a different position to Mr Cooper-Nassington. You are not an officer of this sect, this institution, this organisation, this brotherhood. You are a plain member, free to speak or to hold your tongue. I ask you to remember your pledge to me--to reveal to me all that it is necessary for me to know in this business to satisfy my own conscience, and, remembering this, to tell me what tie binds these people together." "I cannot," he answered, and clasped his hands. "Why?" I demanded sternly, pointing an accusing finger at him. "Why do you refuse? If a man is a monk--a Dominican, a Franciscan, a Norbertine--ay, of any Order you like, even of one of the great silent, enclosed orders like the Trappists or the Cistercians--he does not hesitate to admit his kind and to explain under what rule he lives. Why should you people, here in the very heart of a busy modern city like London, not practise the same candour? Why should you cloak yourselves in mystery, in doubt, in veiled hints, in suspicion? Your reticence is not meaningless. You have some cause for it. What is the reason of it? Why won't you tell me?" "Because we are all alike bound by an oath," he muttered, and he moved away from me as though the mere acknowledgment of that secret bond had set up a new barrier, an unseen gulf, between us. "We cannot tell anyone what we have in mind." "Still there is one way out of the difficulty," put in the MP, speaking now with marked care and deliberation, "which, fortunately, rests with you whether it is acted upon. It is this: While it is quite true we cannot reveal the secrets of our existence to outsiders, no such bar rests against any communications or confidences between members themselves. Why, therefore, Glynn, don't you apply yourself for admission to the Order of St Bruno?" "Impossible," I cried. "I have no wish to join the Order." "Well," said Cooper-Nassington, "I can't pledge the Order, of course--I have no power to--but I am almost certain that they would take you in."