“But how do you know—­” Deever began.

The superintendent cut him short.

“Proceed, if you please,” said he to Nick, and then he fixed his eyes upon Dr. Jarvis.

“In the garden of the hospital,” Nick began, “about half-past six o’clock on the evening of Monday last, you had high words with Patrick Deever, who was working under your direction.”

Dr. Jarvis nodded, as Nick paused.

“He was somewhat intoxicated, and his language was very abusive.  You replied in violent reproval, and he started forward, as if about to attack you.”

Again the doctor made a sign of assent.

“You seized a spade—­”

“It was in my hand,” the doctor interrupted, feebly.

“That is right; correct me whenever I am in error.  You raised the spade and struck Deever upon the head.

“He fell to the ground, and you, bending over him, were horrified to find that he was dead; or, rather, that he seemed to be.

“Exactly how he came to life I do not know, but it must have been while you were in the midst of your terror, and beginning to wonder what you would do with the body.”

“How do you know all this?” asked the doctor, faintly.

“It is simply the only explanation of all the facts.  The witness Klein heard the quarrel and the blow.  That blow did not fall upon you, and there was nobody else present but Patrick Deever.

“Now, then, he suddenly came to himself.  He sprang up.  You were amazed.  You advanced toward him.

“Believing that you intended to renew the attack, he ran away.  He scaled the garden wall, and fled through the little grove toward the river.”

“You are reading my mind,” exclaimed the doctor, whose amazement acted as a restorative.

“No, I am not.  How else could he have got out?  On one side was Klein, on the other St. Nicholas avenue, with many people who would have seen him.  He escaped toward the river.”

“Then you didn’t kill him, after all?” asked the superintendent.

“Of the remainder of that fatal affair,” said Dr. Jarvis, “I have only one explanation to give, and that will seem miraculous.

“His body was found buried in the garden.  I was seen to bury it.  I was seen carrying it there by night.

“But upon my soul, I did not know that I did it.  The evidence has convinced me, that is all.

“And this is the explanation:  Patrick Deever, after escaping from the grove, must have fallen and died.  I must have gone there in my sleep, have found the body, and brought it back to the garden.

“My habit of sleep-walking is well known.  I have done things which, from a scientific point of view, were far more marvelous than this.”

“Nonsense!” cried Deever; “you were wide enough awake.  Superintendent Byrnes will not swallow that story.”

“Is it any more wonderful,” said Nick, “than what I saw the doctor do in his laboratory?”