“Well?” I heard a sinister voice exclaim within the room, and then the door was pushed to; it was not latched. “I did say the seventh!” I called to the lift-boy, and he vanished with his machine. The voice within the room startled me. It gave me furiously to think, as the French say. With a sort of instinctive unpremeditated action I pressed gently against the door till it stood ajar about an inch. And I listened. “It’s a confounded mysterious case to me!” the voice was saying, “that that dose the other day didn’t finish her. We’re running it a dashed sight too close! Here, take this--it’s all ready, label and everything. Substitute the bottles. I’ll run no risks this time. One dose will do the trick inside half an hour, and on that I’ll bet my boots!” “Very well,” said Miss Russell, quite calmly. “It’s pure trinitrin, is it?” “You’re the coolest customer that I ever struck!” the voice exclaimed, in an admiring tone. “Yes, it’s pure trinitrin--beautiful, convenient stuff! Looks like water, no taste, very little smell, and so volatile that all the doctors on the Medical Council couldn’t trace it at a post-mortem. Besides the doctor prescribed a solution of trinitrin, and you got it from the chemist, and in case there’s a rumpus we can shove the mistake on to the chemist’s dispenser, and a fine old row he’ll get into. By the way, what’s the new doctor like?” “Oh! So-so!” said Miss Russell, in her even tones. “It’s a good thing on the whole, perhaps, that I arranged that carriage accident for the first one!” the hard, sinister voice remarked. “One never knows. Get along now at once, and don’t look so anxious. Your face belies your voice. Give us a kiss!” “To-morrow!” said Miss Russell. I hurried away, as it were drunk, overwhelmed with horror and amazement, and turning a corner so as to avoid discovery, reached the second floor by the staircase. I did not wish to meet Miss Russell in the lift.