Herb,
I read a version of this back in mid-00s, and that version had a few examples of how to optimise the blues by using one or more of the principles, including one that said that dogs can feature in the blues. I distinctly remember it said if you involved a blues friendly place, blindness, shooting and dog, you were on a winner. It then gave the example for a good blues opening line ... "I shot a blind dog down in Memphis". That stayed with me for years, and a few years back, I wrote a song with that exact opening line: Kinda funny I'm not sure if that song fits the blues criteria - maybe it's got something to do with my male pattern baldness!
Andrew