"Something to do with it? I should think so, you worthy innocent. Just ring your bell--we'll borrow Mrs. Clayton's sewing-machine oil again. On the night we broke into Foggatt's room you saw the nutshells and the bitten remains of an apple on the sideboard, and you remembered it; and yet you couldn't see that in that piece of apple possibly lay an important piece of evidence. Of course, I never expected you to have arrived at any conclusion, as I had, because I had ten minutes in which to examine that apple, and to do what I did with it. But at least you should have seen the possibility of evidence in it. "First, now, the apple was white. A bitten apple, as you must have observed, turns of a reddish-brown colour if left to stand long. Different kinds of apples brown with different rapidities, and the browning always begins at the core. This is one of the twenty thousand tiny things that few people take the trouble to notice, but which it is useful for a man in my position to know. A russet will brown quite quickly. The apple on the sideboard was, as near as I could tell, a Newtown pippin or other apple of that kind, which will brown at the core in from twenty minutes to half an hour, and in other parts in a quarter of an hour more. When we saw it, it was white, with barely a tinge of brown about the exposed core. Inference--somebody had been eating it fifteen or twenty minutes before--perhaps a little longer; an inference supported by the fact that it was only partly eaten. "I examined that apple, and found it bore marks of very irregular teeth. While you were gone I oiled it over, and, rushing down to my rooms, where I always have a little plaster of Paris handy for such work, took a mould of the part where the teeth had left the clearest marks. I then returned the apple to its place, for the police to use if they thought fit. Looking at my mould, it was plain that the person who had bitten that apple had lost two teeth, one at top and one below, not exactly opposite, but nearly so. The other teeth, although they would appear to have been fairly sound, were irregular in size and line. Now the dead man had, as I saw, a very excellent set of false teeth, regular and sharp, with none missing. Therefore it was plain that _somebody else_ had been eating that apple. Do I make myself clear?" "Quite. Go on."