“Did you never think she had done it?”

Miss Silver met his look.

“I could not do so. Real goodness is a thing quite impossible to mistake. In Miss Mercer’s case it was present as the motive power of all her thoughts and actions. It was the atmosphere in which she lived. She was suffering very deeply, but it was the suffering of innocence in the presence of evil. This was my constant impression. I was therefore brought to the point at which I could not accept Mrs. Latter’s death either as the result of suicide or of murder.”

“In the absence of the Chief, we may perhaps call it an impasse. He won’t let me use French words, you know. He considers them uppish.”

“I have a great respect for Chief Inspector Lamb,” said Miss Silver reprovingly. “A man of real integrity.”

Sergeant Abbott blew her a kiss.

“It’s nothing to the respect I have for you. Continue, revered preceptress.”

Miss Silver gave a very slight cough.

“Really, my dear Frank, you sometimes talk great nonsense. When, as you say, I had reached this impasse, I decided to abandon the external evidence entirely, and to be guided solely by what I felt and had ascertained with regard to the characters of the people concerned. We do not in the animal kingdom expect the tiger to behave like the sheep, or the rabbit to comport itself in the manner natural to the wolf. The Scriptures inform us that we cannot look for grapes on thorns or figs from thistles. An overwhelming passion might shock any of us into the commission of a sudden violent act, but a carefully premeditated poisoning cannot be referred to this category. It must, without fail, be an indication of such evil traits of character as selfishness, inflated self-importance, or perhaps its dangerous opposite, a corroding sense of inferiority. There must be a ruthless disregard of others, a ruthless determination to achieve the desired end no matter what may stand in the way. When I began to look for these characteristics I found them all, with the exception of the inferiority complex, in Mrs. Latter herself. Everyone to whom I talked about her made some contribution to this view of her character. Even seen through the eyes of a grief-stricken and adoring husband, she appeared quite regardless of him or of anyone else who obstructed her wishes. There had been, therefore, one person at Latter End who was qualified to commit cold-blooded and carefully thought-out murder.” She coughed, turned Derek’s stocking, and continued. “But that person was herself the victim. I began to consider in what way she might have been taken in her own trap. I went back to the statements, and I noticed two things. Miss Mercer had watched from the doorway and seen Mrs. Latter putting what she thought was sugar or some sweetening compound into one of the cups. I considered originally that it might have been glucose, which exactly resembles powdered sugar, but I now began to examine the probabilities that it was the powdered morphia. The other point I noticed was that Miss Mercer had apparently stated that she did not see what happened to the coffee cups after she and Mrs. Latter returned from the terrace. The form of the narrative certainly gave the impression that Miss Mercer had followed Mrs. Latter immediately when she left the drawing-room for the terrace, but it was nowhere actually stated, and I began to think that Miss Mercer had not told all she knew, and that she might have altered the position of the cups. I thought it very improbable that Mrs. Latter would have risked leaving both cups together on the tray. When nobody seemed to remember who had placed Mr. Latter’s cup on the table beside his chair, I thought it more than probable that Mrs. Latter had done so herself, in which case Miss Mercer must have seen her do it, since she had her in view from the time she put the powder into the cup until she went out upon the terrace. I became convinced that Miss Mercer had changed the cups. The reason for her silence was obvious. She wished to protect Mr. Latter from the knowledge that his wife had attempted to poison him.”

Frank Abbott gazed at her with unfeigned admiration.

“The nonpareil and wonder of her kind!”

“My dear Frank!”

He said hastily, “Go on-I didn’t mean to interrupt you.”

“That night Miss Mercer walked in her sleep. She would, I am sure, have crossed the hall to the drawing-room, but Miss Julia turned her back. When she said in tones of the deepest distress ‘What have I done!’ I was quite sure that I was on the right track. On the following night, as you know, she again walked in her sleep. This time she re-enacted the events of Wednesday night. With what I had already guessed, it was clear to me that she took an imaginary cup from the tray and set it down by Mr. Latter’s chair. She then came back with her hand still out before her as if it were holding a cup. She came like this as far as the table where the tray had been, and then stretched out her hand again as if she were putting something down. She said, ‘Oh, God-what have I done!’ and I felt quite sure that the mystery was solved.

Next morning at breakfast I had a natural opportunity of enquiring whether Mr. Latter liked his tea or coffee sweet. When I received the reply that he never took more than one lump in either, I concluded that this would be Miss Mercer’s reason for having changed the cups. Meanwhile Polly’s evidence had provided proof that Mrs. Latter had deliberately prepared the powdered morphia.”

“When do you think she took it? Before the scene between Mr. Latter and Miss Mercer on Tuesday evening, when Miss Mercer said she thought the morphia bottle had been moved?”

Miss Silver’s needles clicked.

“Oh, yes, she had taken it before then-possibly whilst the family were at breakfast. You will remember that she had hers in her room. The scene in Mr. Antony’s room had taken place during the night. The idea of getting rid of her husband may not have been a new one, but after that scene I believe she decided to proceed to extremities. Probably all the family knew where Miss Mercer kept the key of her medicine-cupboard. Mrs. Latter found the morphia, took what she wanted, wiped the bottle carefully, and put it back, not inside the box from which she had taken it, but on the shelf. You see, it was certainly part of her plan that Mr. Latter should be supposed to have committed suicide. She therefore left the bottle where it would have been convincingly easy to find. Just before lunch she crushed the tablets and put the powder into that little snuffbox. Then, some time after seven in the evening, Gladys Marsh came to her with her tale of Mr. Latter being in Miss Mercer’s room asking her for something to make him sleep. When she heard that he had actually handled the morphia bottle, that Miss Mercer had told him it was dangerous and he had replied, ‘I don’t care how dangerous it is so long as it makes me sleep,’ she must indeed have felt that she had all the cards in her hand. Consider, for instance-if Miss Mercer had not changed those cups and Mr. Latter had died of morphia poisoning, would there have been any question of murder? There was Gladys Marsh’s evidence that he had said, ‘I don’t care how dangerous it is so long as it makes me sleep’-evidence which Miss Mercer would have been bound to confirm. He had actually handled the morphia bottle. There could have been no suspicion of anything except suicide. A local jury would probably have brought in a verdict of accidental death. They would have taken the line that he was so desperate for sleep as to be reckless of the dose he took, a conclusion warranted by his own words. Mrs. Latter must have thought that the way before her was a safe and easy one. And then Miss Mercer changed the cups.”

Frank looked at her with a sparkle in his eyes.

“The Perfect Moral Tract!” Then, rather hastily, “How much do you suppose Antony had to do with it? Did she go off the deep end about him, or was she just fed to the teeth with Jimmy Latter?”