"Tut, Parker. Miss Thornton herself will give us the ingenious explanation in a moment or two."
Our visitor drew herself up, little spots of red blazing on her cheeks.
"I find your questions offensive, your implications odious and your conclusions entirely erroneous. Mr. Pons."
Solar Pons drew reflectively on his pipe, little stipples of fire making patterns on his thin, ascetic features.
"Indeed. You face it out well enough, Miss Thornton, but you know in your heart that your cruel and ingenious scheme has been discovered. Let us just take things a step farther. When I first visited the studio I did not, of course, know of your possible involvement in the matter. When I learned that you were a brilliant experimental chemist things began to fall into place."
"I see, Pons," I began, light dawning in dark places. "No doubt, Parker," said Solar Pons crisply.
"I had noted that the lager was a special export brand, sealed with foil and a metal cap. That indicated to me that it was unlikely anything could have been introduced into the beer. But it could have acted as a catalyst for something else that should not have been in the food. Where I made my big mistake was in not detecting the substitution earlier. I had asked Mrs. Mandeville and Relph about Tregorran's lunchbut none of us had thought to mention its composition. And then there was the matter of the missing key. You snowed considerable courage in that respect, as indeed, throughout this dreadful business."
Solar Pons paused as though expecting a reply from Celia Thornton, but she remained silent, staring at him with a tight, set face.
"To avoid any suspicion over the locked door, you came — back to the studio at dead of night, let yourself in by the back entrance and replaced the key in the door. Either the officer on duty was asleep or had his back turned. It took tremendous herve but now that I have met you I have no doubt that you would have managed it. And indeed, you would have to have done so, as the key was incontrovertibly back in the door when I examined it, though police and other witnesses had said it was nowhere to be found. It was unfortunate for you that its loss had already been noted."
"I follow you, Pons," I said admiringly.
"A little late, Parker, but I did commend the fact to you," Pons continued.
"If I were to save my client's life there was only one possibility remaining. It was contained in the section of sandwich that fortunately remained unconsumed. I went back to the studio and abstracted it. The police laboratory analysis yielded some interesting information. I have their report here."
Solar Pons smiled thinly and produced some sheets of paper from his pocket.
"But you, as an outstanding chemist, would already know its contents, would you not? Be so good as to glance over this, Parker."
I read the documents with increasing admiration.
"I see, Pons!" I cried excitedly. "Ergot! Of course. The sandwich had been made of rye diseased with ergot."
"Correct," said Pons, biting on the stem of his pipe. "It was an extremely clever and utterly diabolical plot that only a scientist's mind like Miss Thornton's would be capable of conceiving as an instrument of revenge. Bread made with rye diseased with ergotism would affect the victim in what way, Parker?"
"Why, he would very probably go mad, Pons!" I exclaimed. "Ergot produces lysergic acid and in the form of lysergic acid diethylamide would induce a schizophrenic condition."
"Exactly, Parker. As soon as I got this report I studied the literature on the subject. There was a village in France where the local baker produced a batch of bread from diseased rye some years ago. The entire village went mad. There were several deaths, including one where a husband stabbed his wife and a number of people launched themselves from treetops in the erroneous belief that they could fly. I have no doubt Miss Thornton is extremely familiar with the literature."
Solar Pons fixed grim, accusing eyes on Celia Thornton who sank back in her chair.
"A wicked, diabolical plot," he repeated. "Such as could only emanate from the brain of a revenge-crazed woman who was also a very talented scientist."
Celia Thornton half rose from her chair.
"Prove it!" she said defiantly.
"I have already done so," said Solar Pons.
"It is all hearsay!" the woman said wildly. "You have not a scrap of evidence. There is nothing to connect me with having been in the studio."
Solar Pons shook his head. drawing something from his pocket.
"I am sorry to contradict a lady but this object irrefutably places you at the scene of the crime."
He produced a small crimson leather purse that bore the gold monogram C.T.
"Your initials, I believe? I found this beneath the table in the hall of Tregorran's house!"
The woman sprang to her feet, a shocking transformation in her face.
"You are right, Mr. Pons. I did all those things you said. But you will have a hard time proving it. let alone bringing me to court. 'Where is your evidence? We three are alone within these walls. You have taken no notes of our conversation. It will be my word against yours. The whole thing is preposterous."
To my astonishment Solar Pons was smiling.
"I only wanted to hear it from your own lips, Miss Thornton. You have confirmed all my suppositions. As for the purse, you may put your mind at rest. You did not drop it at the scene of the crime. I took it from the hall of your residence yesterday when Dr. Parker and I called on your friend, Miss Annabel Bolton! But it was enough to elicit a confession from you for my purposes."
He turned to me.
"It is true that Miss Thornton could not know exactly what would nappen in that studio. But the end was tragedy and in one blow she would have removed both her rival and her lover if I had not finally put two and two together."
"You have done brilliantly, Pons, as always."
Solar Pons waved away my congratulations.
"Even so, it was an erratic form of revenge, though she might well have driven Tregorran permanently mad. I am told the eating of such diseased material can take that form."
"That is why she locked the door," I said. "In Tregorran's case it took only two hours for the ergot to have that sensational effect. Enhanced, of course by the beer he had drunk, which sent the poison more quickly around his system. In some people it might have taken a deal longer.
Celia Thornton stood facing us with twitching features. She fought to retain control.
"You are very clever, Mr. Pons. Everything you have said is true. But as I have already stated, you will never bring me to trial or clear Tregorran. It is too late for that."
"I think not," said Solar Pons calmly. "You may come in, Inspector Jamison. Ah, there you are, Mecker! I trust you took an accurate note of Miss Thornton's statement?"
Celia Thornton fell back against the table with a cry of anguish and I started up in astonishment as the thick-set form of Inspector Jamison and the officer emerged from the shadowy doorway of Pons' bedroom. I stared at my companion, stupefied.
"We have the statement, Mr. Pons. Celia Thornton, I charge you with complicity in the murder of Sylvia Tregorran by administering a dangerous drug and warn you that anything you say may be taken down and used in evidence."
The girl stared around at us wildly and then collapsed into her chair in a storm of sobbing.
Jamison nodded to Meeker.
"Best take her down to the station," he said awkwardly. "We'll sort out everything there."
When the officer had departed with his distraught charge, Jamison sat down in the vacated place and looked at my companion with grudging admiration.
"Well, Mr. Pons, you have done it again. I take my hat off to you."
"Praise indeed, Inspector," said Solar Pons dryly.
"Though how we're to get through the legal and other tangles I don't know," Jamison continued.