The Haunted Pajamas

It was the first thing I saw that night as I swung into my chambers. Fact is, for the moment, it was the only thing I saw. Somehow, its splash of yellow there under the shaded lamp seemed to catch my eye and hold it.
I screwed my glass tight and examined the thing with interest. Nothing remarkable; just a tiny, oblong package, bearing curious foreign markings, its wrapper plainly addressed to me, but—
By Jove! From China! I ejaculated.
Somebody in far-off China sending me a present, with duties and charges prepaid evidently.
What the deuce was it? I shook it without getting any revelation; then I weighed it in my hand.
The thing was devilish light! In fact, so light that, allowing for outside wrapper and box, dashed if I could see how there was anything at all.
Then I had an awful thought: Suppose, by Jove, they had forgotten to inclose the thing—whatever it was! Jolly tiresome, that, if they had. I felt devilish annoyed.
Really, awfully provoking to do that sort of thing, you know; and I was jolly sure now the dashed thing had been wrapped up empty. I wondered what silly ass I knew in China who would be likely to do a thing like that. I couldn't think of any one at all I knew in China, so I rang for Jenkins.
Anybody I know in China, Jenkins? I asked. And to help him out, I added: Fact is, some chap's sent me a package, you know.
Name on box, sir, perhaps. Said it offhand, just like that—no trouble of thinking, dash it all—never even blinked. Just instinct, by Jove!
And there it was, nicely printed in the corner with a pen:
Roland Mastermann, Government House, Hong Kong, China