Then I turned towards the door, and, without the slightest warning, I felt myself suddenly gripped by the shoulder, while a handkerchief was pressed to my nose and mouth.

I struggled as best I could, but the handkerchief was saturated with chloroform, and I soon lost consciousness.

I hazily remember the man saying to me in short, jerky sentences, spoken at intervals while I was still weakly struggling: "'"'What a fool you must think me, my dear sir! Did you really think that I was going to let you quietly walk out of here, straight to the police-station, eh?
Such dodges have been done before, I know, when a man's silence has to be bought for money.

Find out who he is, see where he lives, give him the money, then inform against him.

No you don't! not this time.