“You’ll come a cropper one of these days,” I observed, rather disgusted by his vanity.
“Do not be enraged, I beg of you, mon ami. I count on you to do me a service—of your friendship.”
“Of course,” I said eagerly, rather ashamed of my moroseness. “What is it?”
“The sleeve of my coat that I have taken off—will you brush it? See you, a little white powder has clung to it. You without doubt observed me run my finger round the drawer of the dressing-table?”
“No, I didn’t.”
“You should observe my actions, my friend. Thus I obtained the powder on my finger, and, being a little over-excited, I rubbed it on my sleeve; an action without method which I deplore—false to all my principles.”
“But what was the powder?” I asked, not particularly interested in Poirot’s principles.
“Not the poison of the Borgias,” replied Poirot, with a twinkle. “I see your imagination mounting. I should say it was French chalk.”
“French chalk?”
“Yes, cabinet-makers use it to make drawers run smoothly.”