I don't know the origin of the quote above, Michael, but I read something regarding dogs in Grant's memoirs. This one regarding Sherman's campaign in Georgia.
The order was given to execute all bloodhounds when found due to their use as runaway slave trackers. A group of Union soldiers, under this order, entered a home, finding a poodle among the residents. The poodle was arrested and, while being removed for execution, it was pointed out to the soldiers that it wasn't a bloodhound.
"No telling what it might grow into when we leave", was the reply.