...it was a huge creature, luminous, ghastly, and spectral. I have cross-examined these men, one of them a hard-headed countryman, one a farrier, and one a moorland farmer, who all tell the same story of this dreadful apparition, exactly corresponding to the hell-hound of the legend. I assure you that there is a reign of terror in the district, and that it is a hardy man who will cross the moor at night.
What is the meaning of it, Watson? said Holmes solemnly as he laid down the paper. "What object is served by this circle of misery and violence and fear? It must tend to some end, or else our universe is ruled by chance, which is unthinkable. But what end? There is the great standing perennial problem to which human reason is as far from an answer as ever.
As Cuvier could correctly describe a whole animal by the contemplation of a single bone, so the observer who has thoroughly understood one link in a series of incidents should be able to accurately state all the other ones, both before and after.