He was following a trail of some kind; whether it was that of the one whom they were seeking was to be learned.

It would take a fine scent to trace the tiny footsteps under the carpet of snow, but such an exploit is not one-tenth as wonderful as that of the trained dogs in Georgia, which will stick to the track of a convict when it has been trampled upon by hundreds of others wearing similar dress and shoes, and will keep to it for miles by running parallel to the trail and at a distance of a hundred feet.
But in the latter case the canines have an advantage at the start; they are put upon the track or directed to hunt for it where it is known to exist; they are given a clew in some form.
The hound Nero was skilful in taking a scent, but his ability was not to be compared to that of the dogs to which I have referred, nor indeed was it necessary that it should be.

But he had great intelligence, and acted as if he understood every word said to him by his master.

He had saved Hugh and his friends many a time by giving warning from afar of the approach of strange parties.

It may seem incredible that he should know what was wanted of him, but there is the best reason for saying he understood it all.