“I can’t say I do.”

“Surely it is evident that it is unequal in its intensity. There is a dot of extravasated blood here, and another there. There are similar indications in this other weal down here. What can that mean?”

“I have no idea. Have you?”

“Perhaps I have. Perhaps I haven’t. I may be able to say more soon. Anything which will define what made that mark will bring us a long way towards the criminal.”

“It is, of course, an absurd idea,” said the policeman, “but if a red-hot net of wire had been laid across the back, then these better marked points would represent where the meshes crossed each other.”

“A most ingenious comparison. Or shall we say a very stiff cat-o’-nine-tails with small hard knots upon it?”

“By Jove, Mr. Holmes, I think you have hit it.”