“Then it was a mushroom that poisoned Jack!” interrupted Lewis, suddenly.  “Some poisonous Amanita got mixed with the edible mushrooms?”

Kennedy answered, quickly, without taking his eyes off the line the needle was tracing: 

“No; this was a case of the deliberate use of the active principle itself, muscarin—­with the expectation that the death, if the cause was ever discovered, could easily be blamed on such a mushroom.  Somehow—­there were many chances—­the poison was slipped into the ramekin Francois was carefully preparing for Mansfield.  The method does not interest me so much as the fact—­”

There was a slight noise from the other room where Mansfield lay.  Instantly we were all on our feet.  Before any of us could reach the door Helen Grey had slipped through it.

“Just a second,” commanded Kennedy, extending the sequin toward us to emphasize what he was about to say.  “The poisoning and the robbery were the work of one hand.  That sequin is the key that has unlocked the secret which my pneumograph has recorded.  Some one saw that robbery committed—­knew nothing of the contemplated poisoning to cover it.  To save the reputation of the robber—­at any cost—­on the spur of the moment the ruse of placing the sequin in the closet occurred.”

Madeline Hargrave turned to Mina, while I recalled Lewis’s remark about Mina’s stepping on the train and tearing it.  The defiance in her black eyes flashed from Madeline to Kennedy.

“Yes,” she cried; “I did it!  I—­”

As quickly the defiance had faded.  Mina Leitch had fainted.

“Some water—­quick!” cried Kennedy.

I sprang through the door into Mansfield’s room.  As I passed I caught sight of Helen Grey supporting the head of Mansfield—­both oblivious to actresses, diamonds, everything that had so nearly caused a tragedy.

“No,” I heard Kennedy say to Lewis as I returned; “it was not Mina.  The person she shielded was wildly in love with her, insanely jealous of Mansfield for even looking at her, and in debt so hopelessly in Mansfield’s ventures that only the big diamond could save him—­Doctor Murray himself!”

III

THE SOUL-ANALYSIS

“Here’s the most remarkable appeal,” observed Kennedy, one morning, as he tossed over to me a letter.  “What do you make of that?” It read: 

Montrose, Conn.

My dear professor Kennedy: 

You do not know me, but I have heard a great deal about you.  Please, I beg of you, do not disregard this letter.  At least try to verify the appeal I am making.

I am here at the Belleclaire Sanatorium, run by Dr. Bolton Burr, in Montrose.  But it is not a real sanatorium.  It is really a private asylum.

Let me tell my story briefly.  After my baby was born I devoted myself to it.  But, in spite of everything, it died.  Meanwhile my husband neglected me terribly.  After the baby’s death I was a nervous wreck, and I came up here to rest.