remembered something else.

"You're quite right. That wasn't how it was done. Listen." And I then
told him of the coco sample which Poirot had taken to be analysed.

John interrupted just as I had done.

"But, look here, Bauerstein had had it analysed already?"

"Yes, yes, that's the point. I didn't see it either until now. Don't you
understand? Bauerstein had it analysed--that's just it! If Bauerstein's
the murderer, nothing could be simpler than for him to substitute some
ordinary coco for his sample, and send that to be tested. And of course
they would find no strychnine! But no one would dream of suspecting
Bauerstein, or think of taking another sample--except Poirot," I added,
with belated recognition.

"Yes, but what about the bitter taste that coco won't disguise?"

"Well, we've only his word for that. And there are other possibilities.
He's admittedly one of the world's greatest toxicologists----"

"One of the world's greatest what? Say it again."

"He knows more about poisons than almost anybody," I explained. "Well,
my idea is, that perhaps he's found some way of making strychnine
tasteless. Or it may not have been strychnine at all, but some obscure
drug no one has ever heard of, which produces much the same symptoms."

"H'm, yes, that might be," said John. "But look here, how could he have
got at the coco? That wasn't downstairs?"

"No, it wasn't," I admitted reluctantly.

And then, suddenly, a dreadful possibility flashed through my mind. I
hoped and prayed it would not occur to John also. I glanced sideways at
him. He was frowning perplexedly, and I drew a deep breath of relief,
for the terrible thought that had flashed across my mind was this: that
Dr. Bauerstein might have had an accomplice.

Yet surely it could not be! Surely no woman as beautiful as Mary
Cavendish could be a murderess. Yet beautiful women had been known to
poison.

And suddenly I remembered that first conversation at tea on the day of
my arrival, and the gleam in her eyes as she had said that poison was a
woman's weapon. How agitated she had been on that fatal Tuesday evening!
Had Mrs. Inglethorp discovered something between her and Bauerstein, and
threatened to tell her husband? Was it to stop that denunciation that
the crime had been committed?

Then I remembered that enigmatical conversation between Poirot and
Evelyn Howard. Was this what they had meant? Was this the monstrous
possibility that Evelyn had tried not to