Page:The Big Four (Christie).pdf/167

 looking at things. Some one gone out—some one come in—two totally different things, Hastings. But if you assumed the wrong one, presently some little discrepancy would creep in and show you that you were on the wrong track.”

“What does all this mean, Poirot.”

Poirot sprang to his feet with sudden energy.

“It means that I have been a triple imbecile. Quick, quick, to the flat in Westminster. We may yet be in time.”

We tore off in a taxi. Poirot returned no answer to my excited questions. We raced up the stairs. Repeated rings and knocks brought no reply, but listening closely I could distinguish a hollow groan coming from within.

The hall porter proved to have a master key, and after a few difficulties he consented to use it.

Poirot went straight to the inner room. A whiff of chloroform met us. On the floor was Sonia Daviloff, gagged and bound, with a great wad of saturated cotton wool over her nose and mouth. Poirot tore it off and began to take measures to restore her. Presently a doctor arrived, and Poirot handed her over to his charge and drew aside with me. There was no sign of Dr. Savaronoff.

“What does it all mean?” I asked, bewildered.

“It means that before two equal deductions