Poirot shook his head, refolding the paper.
"No."
We were both immeasurably surprised.
"There is no arsenic in it," continued Poirot. "But there is antimony.
And that being the case, we will start immediately for Hertfordshire.
Pray Heaven that we are not too late."
It was decided that the simplest plan was for Poirot to represent himself truly as a detective, but that the ostensible reason of his visit should be to question Mrs. Templeton about a servant formerly in her employment whose name he obtained from Nurse Palmer, and who he could represent as being concerned in a jewel robbery.
It was late when we arrived at Elmstead, as the house was called.
We had allowed Nurse Palmer to precede us by about twenty minutes, so that there should be no question of our all arriving together.
Mrs. Templeton, a tall dark woman, with sinuous movements and uneasy eyes, received us.
I noticed that as Poirot announced his profession, she drew in her breath with a sudden hiss, as though badly startled, but she answered his question about the maid-servant readily enough.
And then, to test her, Poirot embarked upon a long history of a poisoning case in which a guilty wife had figured.
His eyes never left her face as he talked, and try as she would, she could hardly conceal her rising agitation.
Suddenly, with an incoherent word of excuse, she hurried from the room.
We were not long left alone.
A squarely-built man with a small red moustache and pince-nez came in.
"Dr. Treves," he introduced himself. "Mrs. Templeton asked me to make her excuses to you.
She's in a very bad state, you know. Nervous strain.
Worry over her husband and all that.
I've prescribed bed and bromide.
But she hopes you'll stay and take pot luck, and I'm to do host.
We've heard of you down here, M. Poirot, and we mean to make the most of you.
Ah, here's Micky!"
A shambling young man entered the room.
He had a very round face, and foolish-looking eyebrows raised as though in perpetual surprise.
He grinned awkwardly as he shook hands.
This was clearly the "wanting" son.
Presently we all went in to dinner.
Dr. Treves left the room - to open some wine, I think - and suddenly the boy's physiognomy underwent a startling change.
He lent forward, staring at Poirot.
"You've come about father," he said, nodding his head. "I know.
I know lots of things - but nobody thinks I do.
Mother will be glad when father's dead and she can marry Dr. Treves.
She isn't my own mother, you know.
I don't like her.
She wants father to die."
It was all rather horrible.
Luckily, before Poirot had time to reply, the doctor came back, and we had to carry on a forced conversation.
And then suddenly Poirot lay back in his chair with a hollow groan.
His face was contorted with pain.
"My dear sir, what's the matter?" cried the doctor.
"A sudden spasm.
I am used to them.
No, no, I require no assistance from you, doctor.
If I might lie down upstairs."
His request was instantly acceded to, and I accompanied him upstairs, where he collapsed on the bed, groaning heavily.
For the first minute or two I had been taken in, but I had quickly realised that Poirot was - as he would have put it - playing the comedy, and that his object was to be left alone upstairs near the patient's room.
Hence I was quite prepared when, the instant we were alone, he sprang up.
"Quick, Hastings, the window.
There is ivy outside.