"My dear Holmes!" "I have notes of several similar cases, though none, as I remarked before, which were quite as prompt. My whole examination served to turn my conjecture into a certainty. Circumstantial evidence is occasionally very convincing, as when you find a trout in the milk, to quote Thoreau's example." "But I have heard all that you have heard." "Without, however, the knowledge of pre-existing cases which serves me so well. There was a parallel instance in Aberdeen some years back, and something on very much the same lines at Munich the year after the Franco-Prussian War. It is one of these cases—but, hullo, here is Lestrade! Good-afternoon, Lestrade! You will find an extra tumbler upon the sideboard, and there are cigars in the box." The official detective was attir