“The writing on the wall was done with a man’s forefinger dipped in blood. My glass allowed me to observe that the plaster was slightly scratched in doing it, which would not have been the case if the man’s nail had been trimmed. I gathered up some scattered ash from the floor. It was dark in colour and flakey⁠—such an ash as is only made by a Trichinopoly. I have made a special study of cigar ashes⁠—in fact, I have written a monograph upon the subject. I flatter myself that I can distinguish at a glance the ash of any known brand, either of cigar or of tobacco. It is just in such details that the skilled detective differs from the Gregson and Lestrade type.”

“And the florid face?” I asked.

“Ah, that was a more daring shot, though I have no doubt that I was right. You must not ask me that at the present state of the affair.”