But at last the perfect opportunity came. I received a letter from a
botanical paper asking for an article on the Flora of Trench Life.
"Horray!" said Celia. "There you are."
I sat down and wrote the article. Working up gradually to the subject of
rats, and even more gradually intertwining it, so to speak, with the
subject of cats, I brought off in one perfect climax the great Joke.
"Lovely!" said Celia excitedly.
"There is one small point which has occurred to me. Rats are _fauna_, not
_flora_; I've just remembered."
"Oh, does it matter?"
"For a botanical paper, yes."
And then Celia had a brilliant inspiration.
"Send it to another paper," she said.
I did. Two days later it appeared. Considering that I hadn't had a proof,
it came out extraordinarily well. There was only one misprint. It was at
the critical word of the Joke.