Hmm, well I searched the Scribd copy of ‘Surprised by Joy’ for the keywords dog, jacksie, jack, four, and killed, but wasn’t noticing the passage in question.

I searched some more. Bruce L. Edwards says in his 2007 biography that Douglas Gresham is the only source for the childhood dog story. It seems like something Warnie would’ve mentioned so I continue to be skeptical of Douglas Gresham on this point. The story is strange: Lewis demanded to be called the slang term for ‘anus’. The dog story could be generated later as cover.