Approximately 100 hours after the knitting disappeared, the ball of yarn reappeared at the foot of the back stairs.
The yarn remained in a ball, thanks be to Dog.
I can now attest that the knitting chewed off the needle had already been seen in the backyard. (Stomach acid apparently turns the green in Cottontots yarn yellow.)
The patient is resting comfortably after a wee smackerel of bland, prescription dog food.
Pure Luck and I will sleep tonight.