“Then I’d better bring you the powders myself,” decided the Doctor.  “The pharmacy closes at eleven.  I shall have to make them up myself.”

“That seems a lot of trouble.”

“Nothing is any trouble if I can be helpful,” he assured her, smilingly.  And Miss Cornelia also smiled, took the piece of paper from his hand, glanced at it once, as if out of idle curiosity about the unfinished prescription, and then laid it down on the table with a careless little gesture.  Dale gave her aunt a glance of dumb entreaty.  Miss Cornelia read her wish for another moment alone with the Doctor.

“Dale will let you out, Doctor,” said she, giving the girl the key to the front door,

The Doctor approved her watchfulness.

“That’s right,” he said smilingly.  “Keep things locked up.  Discretion is the better part of valor!”

But Miss Cornelia failed to agree with him.

“I’ve been discreet for sixty-five years,” she said with a sniff, “and sometimes I think it was a mistake!”

The Doctor laughed easily and followed Dale out of the room, with a nod of farewell to the others in passing.  The detective, seeking for some object upon whom to vent the growing irritation which seemed to possess him, made Bailey the scapegoat of his wrath.

“I guess we can do without you for the present!” he said, with an angry frown at the latter.  Bailey flushed, then remembered himself, and left the room submissively, with the air of a well-trained servant accepting an unmerited rebuke.  The detective turned at once to Miss Cornelia.

“Now I want a few words with you!”

“Which means that you mean to do all the talking!” said Miss Cornelia acidly.  “Very well!  But first I want to show you something.  Will you come here, please, Mr. Anderson?”

She started for the alcove.

“I’ve examined that staircase,” said the detective.

“Not with me!” insisted Miss Cornelia.  “I have something to show you.”

He followed her unwillingly up the stairs, his whole manner seeming to betray a complete lack of confidence in the theories of all amateur sleuths in general and spinster detectives of sixty-five in particular.  Their footsteps died away up the alcove stairs.  The living-room was left vacant for an instant.

Vacant?  Only in seeming.  The moment that Miss Cornelia and the detective had passed up the stairs, the crouching, mysterious Unknown, behind the settee, began to move.  The French window-door opened—­a stealthy figure passed through it silently to be swallowed up in the darkness of the terrace.

And poor Lizzie, entering the room at that moment, saw a hand covered with blood reach back and gropingly, horribly, through the broken pane, refasten the lock.

She shrieked madly.

CHAPTER FOURTEEN

HANDCUFFS