The mood of the story is one of surrealism and black humor. Here is an old man selling love potions and undetectable poisons in the wide open in a shop in modern Manhattan. He must be well known because he has been recommended to the young man who enters.
"Is it true," asked Alan, "that you have a certain mixture that has--er--quite extraordinary effects?"
New York is such a big and populous city that it just seems remotely possible that there could be someone somewhere who would be dealing in love potions and undetectable poisons. The old man knows what Alan Austen is looking for, but he introduces a different item immediately.
"Here, for example," interrupted the old man, reaching for a bottle from the shelf. "Here is a liquid as colorless as water, almost tasteless, quite imperceptible in coffee, milk, wine, or any other beverage. It is also quite imperceptible to any known method of autopsy."
Throughout the story the old man makes allusions to this colorless liquid. He calls it a...
(The entire section contains 584 words.)