“Of course, there was Borland himself,” answered Winslow.  “Then there was a young chemist named Lathrop, a very clever and ambitious fellow who succeeded Cushing when he resigned from the works, and Dr. Harris, who was persuaded to go because of his friendship for Borland.  After they took up the concession I believe all of them put money into it, though how much I can’t say.”

I was curious to ask whether there were any other visitors at the Winslow house who might be rivals for Ruth’s affections, but there was no opportunity.

Nothing more was said until we arrived at Goodyear.

We found the body of Cushing lying in a modest little mortuary chapel of an undertaking establishment on the main street.  Kennedy at once began his investigation by discovering what seemed to have escaped others.  About the throat were light discolourations that showed that the young inventor had been choked by a man with a powerful grasp, although the fact that the marks had escaped observation led quite obviously to the conclusion that he had not met his death in that way, and that the marks probably played only a minor part in the tragedy.

Kennedy passed over the doubtful evidence of strangulation for the more profitable examination of the little gash in the wrist.

“The radial artery has been cut,” he mused.

A low exclamation from him brought us all bending over him as he stooped and examined the cold form.  He was holding in the palm of his hand a little piece of something that shone like silver.  It was in the form of a minute hollow cylinder with two grooves on it, a cylinder so tiny that it would scarcely have slipped over the point of a pencil.

“Where did you find it?” I asked eagerly.

He pointed to the wound.  “Sticking in the severed end of a piece of vein,” he replied, half to himself, “cuffed over the end of the radial artery which had been severed, and done so neatly as to be practically hidden.  It was done so cleverly that the inner linings of the vein and artery, the endothelium as it is called, were in complete contact with each other.”

As I looked at the little silver thing and at Kennedy’s face, which betrayed nothing, I felt that here indeed was a mystery.  What new scientific engine of death was that little hollow cylinder?

“Next I should like to visit the laboratory,” he remarked simply.

Fortunately, the laboratory had been shut and nothing had been disturbed except by the undertaker and his men who had carried the body away.  Strong had left word that he had gone to Boston, where, in a safe deposit box, was a sealed envelope in which Cushing kept a copy of the combination of his safe, which had died with him.  There was, therefore, no hope of seeing the assistant until the morning.

Kennedy found plenty to occupy his time in his minute investigation of the laboratory.  There, for instance, was the pool of blood leading back by a thin dark stream to the workbench and its terrible figure, which I could almost picture to myself lying there through the silent hours of the night before, with its life blood slowly oozing away, unconscious, powerless to save itself.  There were spurts of arterial blood on the floor and on the nearby laboratory furniture, and beside the workbench another smaller and isolated pool of blood.