“Now we will take another line of reasoning. When you follow two separate chains of thought, Watson, you will find some point of intersection which should approximate to the truth. We will start now, not from the lady but from the coffin and argue backward. That incident proves, I fear, beyond all doubt that the lady is dead. It points also to an orthodox burial with proper accompaniment of medical certificate and official sanction. Had the lady been obviously murdered, they would have buried her in a hole in the back garden. But here all is open and regular. What does this mean? Surely that they have done her to death in some way which has deceived the doctor and simulated a natural end⁠—poisoning, perhaps. And yet how strange that they should ever let a doctor approach her unless he were a confederate, which is hardly a credible proposition.”

“Could they have forged a medical certificate?”