“The Scotch Terrier is generally low in stature, seldom more than twelve or fourteen inches in height, with a strong muscular body, and short and stout legs; his ears are small and half-pricked; his head is rather large in proportion to the size of his body, and the muzzle considerably pointed; his scent is exceptionally acute, so that he can trace the footsteps of other animals with certainty: he is generally of a sand-colour or black. Dogs of these colours are certainly the most hardy, and more to be depended upon. When white or pied, it is a sure mark of the impurity of the breed. The hair of the Terrier is long, matted, and hard, over almost every part of his body. His bite is extremely keen.”
Excerpt from Biological Sketches and Anecdotes of the Dog – Published 1829 – Author Capt. Thomas Brown