When we were settled in the laboratory once more Kennedy plunged with renewed vigor into the investigation he had dropped in the morning in order to make the hurried trip to the Phelps home in Tarrytown.

I had hoped he would talk further of the probabilities of the connection of the various people with the crime, but he had no comment even upon the admission of Enid that she had known Millard for a period long antedating the trouble with Stella Lamar.

It seemed that, after all, he was quite excited at the discovery of the ampulla and was anxious to begin the analysis of its scale-like contents.  I was not sure, but it struck me that this might be the same substance which had spotted the towel or the portieres.  If that were so, the finding of it in this form had given him a new and tangible clue to its nature, accounting for his eagerness.

I watched his elaborate and thorough preparations, wishing I could be of assistance, but knowing the limitations of my own chemical and bacteriological knowledge.  I grasped, however, that he was concentrating his study upon the spots he had cut from the portieres, in particular the stain where the point of the needle had been, and upon the incrustations on the inner surface of the tube.  He made solutions of both of these and for some little time experimented with chemical reactions.  Then he had recourse to several weighty technical books.  Though bursting with curiosity, I dared not question him, nor distract him in any way.

Finally he turned to a cage where he kept on hand, always, a few of those useful martyrs to science, guinea pigs.  Taking one of the little animals and segregating him from the others, he prepared to inoculate him with a tiny bit of the solution made from the stain on the piece cut from the portiere.

At that I knew it would be a long and tiresome analysis.  It seemed a waste of time to wait idly for Kennedy to reach his conclusions, so I cast about in my mind for some sort of inquiry of my own which I could conduct meanwhile, perhaps collecting additional facts about those we were watching at the studio.

Somehow I could not wholly lose my suspicions of the director, Werner; especially now as I marshaled the evidence against him.  First of all he was the only person absolutely in control of the movements of Stella Lamar.  If she did not bring up her arm against the curtains in a manner calculated to press the needle against her flesh it certainly would not seem out of the way for him to ask her to do it over again, or even for him to direct changes in her position.  This he could do either in rehearsal or in retakes after the scene had actually been photographed.  It was not proof, I knew.  Practically all of them were familiar with the action of the scene, could guess how Werner would handle it.  The point was that the director, next to Millard, was the most thoroughly conversant with the scenes in the script, had to figure out everything down to the very location and angles of the camera.