What's up with the Horse's Mouth?

In the wake of the recently run Kentucky Derby, I thought it would be appropriate to investigate the old saying, "the horse's mouth."

The phrase was used in the days when the horse was the sole means of transportation. A buyer of a horse needed to know the true age and health of the horse; thus, this essential knowledge could be determined through a dental exam. If the buyer of the horse had a reason to distrust the veracity of the seller's claims, the truth could be determined from "the horse's mouth."

Since those days, the old saying has come to mean going straight to the source to get the true information.

Thanks to John Rosemond, "Living with Children," the Washington Times, May 6,02007.