"It wasn't the time to ask for an explanation," continued the doctor. "You remember, Betty, that Eunice took you in her arms, and told you very gently what had happened. She tried to persuade you not to go in the room, but you refused to be put off. Effingham came and unlocked the door; you and I went in and looked at him still lying by the side of the big desk. It was then that I saw the despatch-box, and wondered why I had not noticed it before, especially as it was just the link that I needed to fit into the accident hypothesis."
"I don't think I have any theory," answered Doctor Marcy. "Up to this moment my mind had been more concerned with the stark fact of Graeme's death than with the predisposing cause. Of course I had taken the temple bruise into account, and in a superficial way it seemed to explain everything. But I really hadn't tried to formulate my ideas clearly. The thought of you, Betty, had presented itself, and I was chiefly engaged in wondering how you were to be told and how you would take the shock."
"But afterwards?" persisted Betty.
"Then I tried to build up the accident theory. Everything fitted beautifully except for the little uncertainty about the despatch-box."
"May I ask a question or two," I interrupted.
"Surely."
"You say that you left Effingham to guard the library door while you went to meet my Cousin Betty?"
"Yes."
"How long were you away?"
"Approximately five minutes."