The last part of this conversation was held as Nick, Deever and Klein passed out upon the street.

A ragged young man who was leaning against a tree heard it, and was much surprised.

For the ragged young man was Patsy, and he had never heard Nick Carter ask anybody except his regular assistants to help him in that way before.

CHAPTER II.

The dead man’s head.

Dr. Jarvis, chief of the staff of St. Agnes’ Hospital, was well known as a peculiar man.

He was rich enough to take his leisure, but he worked like a slave.  He had an elegant house on St. Nicholas avenue, but he spent all his days and more than half his nights at the hospital.

A rude cot in a little room adjoining his laboratory in the hospital was his bed four nights in seven on the average.  His only recreation was found in the care of a little garden in the hospital grounds; and it was the common talk of the younger physicians that Dr. Jarvis enjoyed finding fault with the gardener more than he did cultivating the flowers.

He had a wife and a young, unmarried daughter, whom he loved devotedly, but to whom he gave only a few hours of his time in the course of a week.

A negro named Caesar Augustus Cleary was the doctor’s assistant in the laboratory.

The other physicians in the hospital said that Cleary had become so accustomed to Jarvis’ ways that, like a Mississippi mule, he had to be cursed before he could be made to understand anything.

Cleary slept in a little closet similar to the doctor’s, and on the opposite side of the laboratory.  He was asleep there, about twelve o’clock on the night after Nick’s visit to Lawrence Deever, when Nick crept softly through the window.

All these rooms were on the ground floor and entrance was easy.

Nick had spent a part of the evening in the garden.  He had watched till the light went out in the laboratory and another appeared in the doctor’s bed-room.  Then he was ready for a search of the premises.

If, in a moment of anger, Dr. Jarvis had struck Patrick Deever and killed him, it was likely that the laboratory would hold some trace of the secret.

The best way to hide a human body is to utterly destroy it.  This is no easy task for an ordinary man, but to a scientist, like Dr. Jarvis, it would be comparatively easy.

However, it would take time.  Patrick Deever had disappeared on Monday night.  Forty-eight hours had elapsed, but yet Nick hoped to find a trace, if the work of destruction had been attempted in the laboratory.

Nick had entered Cleary’s room with the purpose of guarding against any interruption from the negro.  He found Cleary sleeping heavily; but when Nick left the room and glided into the laboratory, Cleary’s sleep was even deeper than it had been before.