Brown-black hound mix named Scout, lost in Northampton

I’m missing Scout, a five-year-old brown-black hound mix about 50 pounds. He wears a blue nylon collar with a red name tag that says 'Scout' and a small reflective stripe. Yesterday around 3pm we were on Main Street by Smith College near the campus market area when a passerby startled him and he bolted toward the river path behind the Northampton Athletic Center. He has a white patch on his chest and a slight limp in his left hind leg. He’s friendly, really attached to me, and this dog means the world to me—please help me bring him home; text 413-555-0189 or email [email protected] if you see him.