"I don't think that at the time any one in the room realized how important the doctor's statement was, a statement which, by the way, was confirmed in all its details by the district medical officer, who had conducted the postmortem. Mrs. Hazeldene had died suddenly from an injection of prussic acid, administered no one knew how or when. She had been travelling in a first-class railway carriage in a busy time of the day. That young and elegant woman must have had singular nerve and coolness to go through the process of a self-inflicted injection of a deadly poison in the presence of perhaps two or three other persons. "Mind you, when I say that no one there realized the importance of the doctor's statement at that moment, I am wrong; there were three persons, who fully understood at once the gravity of the situation, and the astounding development which the case was beginning to assume. "Of course, I should have put myself out of the question," added the weird old man, with that inimitable self-conceit peculiar to himself. "I guessed then and there in a moment where the police were going wrong, and where they would go on going wrong until the mysterious death on the Underground Railway had sunk into oblivion, together with the other cases which they mismanage from time to time. "I said there were three persons who understood the gravity of the two doctors' statements--the other two were, firstly, the detective who had originally examined the railway carriage, a young man of energy and plenty of misguided intelligence, the other was Mr. Hazeldene. "At this point the interesting element of the whole story was first introduced into the proceedings, and this was done through the humble channel of Emma Funnel, Mrs. Hazeldene's maid, who, as far as was known then, was the last person who had seen the unfortunate lady alive and had spoken to her. "'Mrs. Hazeldene lunched at home,' explained Emma, who was shy, and spoke almost in a whisper; 'she seemed well and cheerful. She went out at about half-past three, and told me she was going to Spence's, in St. Paul's Churchyard, to try on her new tailor-made gown. Mrs. Hazeldene had meant to go there in the morning, but was prevented as Mr. Errington called.' "'Mr. Errington?' asked the coroner casually. 'Who is Mr. Errington?' "But this Emma found difficult to explain. Mr. Errington was--Mr. Errington, that's all. "'Mr. Errington was a friend of the family. He lived in a flat in the Albert Mansions. He very often came to Addison Row, and generally stayed late.' "Pressed still further with questions, Emma at last stated that latterly Mrs. Hazeldene had been to the theatre several times with Mr. Errington, and that on those nights the master looked very gloomy, and was very cross.