Having once been hit and bruised, in puppyhood, by a motor car, the dog had a wholesome respect for such rapid and ill-smelling vehicles.

Thus, as he saw the lights and heard the engine-purr of one of them, coming toward him, down the road, he dodged back into the wayside hedge until it passed.

Which is the reason Milo Standish failed to see the dog he had been hunting for.
A little later, Brice's scent became so distinct that the collie could abandon his nose-to-the-ground tactics and strike across country, by dead-reckoning, guided not only by his nose but by the sound of Gavin's steps.

Then, in an access of delight, he burst upon the plodding man.
"Why, Bobby!" exclaimed Brice, touched by the dog's rapture in having found him again.

"Why, Bobby Burns! What on earth made you follow me?
Don't you know I'm not your master?
Don't you, Bobby ?" He was petting the frisking collie as he talked.