"It would be heavenly! It's so stupid going alone, hardly any fun at all.... Of course, I don't know what the doctor would think if I began running about like that. He probably wouldn't approve."

"Do you like him?" asked her companion suddenly.

"Dr. Sartorius?" she replied, knitting her brows. "I hardly know....

I suppose the fact is I neither like nor dislike him. I admire him very much indeed; I think he's a frightfully clever physician and scientist."

"But as a man?"

"I don't believe he is a man, quite," she laughed. "At least, one can't exactly think of him as one."

"That's how he strikes me. Yet I suppose no one can be as phlegmatic as he seems; there must be a spark of enthusiasm in him somewhere."

"Oh, but there is! Don't you know? He absolutely lives for research; it's the one thing he takes an interest in. He practises medicine to make a living, but he devotes every spare minute to hunting for anti-toxins."

"Does he indeed? I know my aunt thinks very highly of him, but I'm glad you do, too. Your opinion is worth something."

The time pa.s.sed with amazing quickness, as they discovered when they consulted their watches.

"Must you go back at once?" Roger asked as he tentatively reversed the car and slowly headed for home.

"I don't want to be late," she said with a sigh. "It's my first case here; I must be on my best behaviour! But--I've just thought of something. Would it be very far out of our way if we went to the doctor's villa in the Route de Gra.s.se? I left my French lesson-books there, and I'd like to fetch them."

"We can do it easily; only show me the house."

Before long they came in sight of the villa, which looked as tidy, as smug and non-committal as it had done when she first approached it some weeks ago. Alighting quickly from the car, Esther rang the bell and waited, expecting momentarily to see the friendly Jacques answer the summons. There was, however, no response.

"Is anyone staying here?" asked Roger.

"Yes, the doctor's servant, but he may have gone out."

She rang again; from the distant kitchen they could hear the faint persistent peal.

"The place looks deserted for the moment, at any rate," Roger remarked, gazing up at the closed windows.

With a sudden wry smile, Esther fished in her bag and produced a latch-key.

"Isn't it stupid of me? I'd forgotten I still had it. I've meant daily to give it back to the doctor, but I never think of it at the right moment."

She fitted the key into the Yale lock, and in another moment the two were standing inside the dim and chilly hall, looking about them. A few circulars lay in a heap on the floor, there was a film of dust on the polished parquet. A man's overcoat and hat adorned the rack. From the salon a clock ticked loudly.

"Gloomy place, this," commented Roger, glancing into the cold and orderly salon. "Makes me think of funerals."

"Yes, that room is always like that, only used as a reception-room for patients."

She flung open the door of the salle a manger and entered, then stopped, looking about her.

"This looks as though Jacques had been entertaining his friends," she said, pointing to the collection of bottles on the sideboard and the syphon and whisky decanter on the table.

"By Jove, it does!"

Roger ran his eyes over the miniature bar.

"Martini vermouth, Noilly Prat, Gordon gin, Angostura, Bacardi rum, absinthe--pre-war, at that. If your Jacques mixes all these drinks----"

"I never saw Jacques take anything except a little _vin ordinaire_,"

Esther replied, shaking her head. "But there have certainly been two people here, whoever they were, for here are their two gla.s.ses."

As she spoke she picked up the tumblers from the table one after the other and examined them thoughtfully. One, she discovered, had had only soda-water in it, there was a little in the bottom now, with a cigarette-end floating about--a cigarette with a red tip, half uncurled from the wet. She frowned at it for a moment, then went to the book-shelves in search of her books, which she discovered among a pile of medical journals.

"Here they are. Shall we go?"

Roger was examining the tumbler she had recently set down.

"Jacques also seems to have a nice taste in cigarettes," he remarked.

"Extravagant fellow altogether."

He indicated the floor, which was littered with stubs, mostly cork-tipped, though there was an occasional scarlet tip here and there.

"Jacques smokes only those cheap Marylands that come in a blue packet,"

Esther replied, laughing. "You see I'm acquainted with all his habits.

No, I can't believe it is Jacques who's been here; it looks as though..."

She stopped and, bending down, picked up a tiny object from the rug.

"There was a woman, at any rate," she mused, with a considerable degree of curiosity in her voice, "for here is a hairpin."

It was a little bronze one of the "invisible" sort. Utterly unable to comprehend any woman's being in this house, she turned the hairpin over wonderingly. Then she noticed that her companion was staring up at the ceiling with a frown on his face.

"S'sh," he cautioned, laving a hand on her arm. "I thought I heard..."

"_Who the h.e.l.l is that down there? Answer, or I'll shoot!_"

They jumped guiltily, astonished at the sudden angry voice that thundered upon them from the upper regions of the house.

"Goodness!" whispered Esther, gazing at Roger with round eyes. "Who do you suppose----"

"I say, whose b.l.o.o.d.y business is it to prowl about down there? Here, show yourselves, d.a.m.n you!"

It was a man's voice, at once sleepy and peevish.

"Who on earth is it?"

"I'll soon see."

Roger pushed the door wide and strode into the hall, Esther closely following.