“What’s the matter?” asked the head waiter anxiously.

Already the new-comer was supporting Mr. Grimm on his knee, and flicking water in his face.

“Nothing serious, I fancy,” he answered shortly.  “He’s subject to these little attacks.”

“What are they?  Who is he?”

The stranger tore at Mr. Grimm’s collar until it came loose, then he fell to chafing the still hands.

“He is a Mr. Grimm, a government employee—­I know him,” he answered again.  “I imagine it’s nothing more serious than indigestion.”

A little knot had gathered about them, with offers of assistance.

“Waiter, hadn’t you better send for a physician?” some one suggested.

“I’m a physician,” the stranger put in impatiently.  “Have some one call a cab, and I’ll see that he’s taken home.  It happens that we live in the same apartment house, just a few blocks from here.”

Obedient to the crisply-spoken directions, a cab was called, and five minutes later Mr. Grimm, still insensible, was lifted into it.  The stranger took a seat beside him, the cabby touched his horse with a whip, and the vehicle fell into the endless, moving line.

XXI

A SLIP OF PAPER

When the light of returning consciousness finally pierced the black lethargy that enshrouded him, Mr. Grimm’s mind was a chaos of vagrant, absurd fantasies; then slowly, slowly, realization struggled back to its own, and he came to know things.  First was the knowledge that he was lying flat on his back, on a couch, it seemed; then, that he was in the dark—­an utter, abject darkness.  And finally came an overwhelming sense of silence.

For a while he lay motionless, with not even the movement of an eye-lash to indicate consciousness, wrapped in a delicious languor.  Gradually this passed and the feeble flutter of his heart grew into a steady, rhythmic beat.  The keen brain was awakening; he was beginning to remember.  What had happened?  He knew only that in some manner a drug had been administered to him, a bitter dose tasting of opium; that speechlessly, he had fought against it, that he had risen from the table in the restaurant, and that he had fallen.  All the rest was blank.

With eyes still closed, and nerveless hands inert at his sides he listened, the while he turned the situation over in speculative mood.  The waiter had administered the drug, of course, unless—­unless it had been the courteous stranger who had replaced the newspaper on the table!  That thought opened new fields of conjecture.  Mr. Grimm had no recollection of ever having seen him before; and he had paid only the enforced attention of politeness to him.  And why had the drug been administered?  Vaguely, incoherently, Mr. Grimm imagined that in some way it had to do with the great international plot of war in which Miss Thorne was so delicate and vital an instrument.