For what it is worth, I awoke one evening this last year to find my friends cat creeping forward on my chest with her mouth very close to my own. My idea is that she was interested in my breath, though not due to any connection to a possible soul, but merely as a scent. I have awoke several times to similar behavior and feel just as soulful as ever. My conclusion is that similar nocturnal ventures in the annals of cat curiosity may have led people to create this myth. They are damn strange creatures.
Welcome, motherengine, to the Straight Dope Message Board! Sit down, put your feet up, relax, look around, and we hope you enjoy your stay. I think you will find we are an interesting bunch of loonie… er, people. 
When starting a thread around here about one of Uncle Cecil’s columns, we like to put a link to the column in the opening post. You can do this by cutting and pasting the url from your web browser’s address field, like this: http://boards.straightdope.com/sdmb/showthread.php?t=465968 . This helps everyone be certain which of the Perfect Master’s threads you are referencing.
In this case, I presume you are talking about What’s the origin of the myth that cats can suck the breath out of babies?
Hope you have fun, and again, welcome. 
Forget about the soul reference of the first post. I was thinking of a different aspect of the myth not directly addressed in the original question. Godspeed.
Or possibly even this one, FIXED LINK
Hehehe, um, yeah. :eek:
My cat’s breath smells like babes.
I took in a feral kitten once and woke up the next morning to find her sitting on my chest. I only caught a glimpse of her before having to shut my eyes again, because she had apparently been eyeing my eyes with the idea of catching them when they came out!
I suffered only the odd sensation of having my eyelids batted (tentatively, at that). Otherwise I escaped without injury.