"Remember that nothing else in the way of identification is of any use, for I doubt if either of us has ever seen the real, undisguised Dawson as he is known to God. We know a man whom we think is the genuine article--but is he? Cary's description of him is most unlike the man whom we see here. I expect that he has a different identity for every place which he visits. If he told me that at any moment he was wholly undisguised, I should be quite sure that he was lying. The man wallows in deception for the very sport of the thing. But he can't change his ears. Study them, and you will be safe." Our club was the only place in which we could be sure that Dawson did not penetrate, though I should not have been surprised to learn that one or two of the waitresses were in his pay. Dawson is an ardent feminist; he says that as secret agents women beat men to a frazzle. Shortly before Dawson left for his headquarters on the north-east coast he dropped in upon me. He had finished his researches, and revealed the results to me with immense satisfaction. "I have fixed up Menteith," he began, "and know exactly how he came into communication with the German Secret Service." The contemptuous emphasis which he laid on the word "Secret" would have annoyed the Central Office at Potsdam. I have given the detected British spy the name of Menteith after that of the most famous traitor in Scottish history; if I called him, say, Campbell or Macdonald, nothing could save me from the righteous vengeance of the outraged Clans.