Whiskers Under the Chin

I wonder how this particular style came about. Was it meant to cover a scar? Or an unsightly adam's apple? Dirty collars?

By Sarony
Gold Medal Paris, 1878
37 Union Square
New York
Elevator from the Street
Cabinet card, 4.25 x 6.5 inches

3.25 x 2.5 inches

By Stone's Great Northern
Photo. and Copying House
Potsdam, N.Y.
Carte de Visite, 2.5 x 4.25 inches