“Send her off at once, then, to watch a Mrs. Irene Heron of Flat C, Truro Mansions, Chelsea, till further notice.”

“Precisely,” said Mr. Polteed; “divorce, I presume?” and he blew into a speaking-tube. “Mrs. Blanch in? I shall want to speak to her in ten minutes.”

“Deal with any reports yourself,” resumed Soames, “and send them to me personally, marked confidential, sealed and registered. My client exacts the utmost secrecy.”

Mr. Polteed smiled, as though saying, “You are teaching your grandmother, my dear sir;” and his eyes slid over Soames’ face for one unprofessional instant.

“Make his mind perfectly easy,” he said. “Do you smoke?”

“No,” said Soames. “Understand me: Nothing may come of this. If a name gets out, or the watching is suspected, it may have very serious consequences.”

Mr. Polteed nodded. “I can put it into the cipher category. Under that system a name is never mentioned; we work by numbers.”

He unlocked another drawer and took out two slips of paper, wrote on them, and handed one to Soames.

“Keep that, sir; it’s your key. I retain this duplicate. The case we’ll call 7x. The party watched will be 17; the watcher 19; the Mansions 25; yourself—I should say, your firm—31; my firm 32, myself 2. In case you should have to mention your client in writing I have called him 43; any person we suspect will be 47; a second person 51. Any special hint or instruction while we’re about it?”

“No,” said Soames; “that is—every consideration compatible.”