And he showed what he meant. Every other part of the door glistened with freshly applied varnish; but the octagonal region remained dull, as though no liquid had ever touched it. Johnson dipped his brush into the can, and applied a liberal smear of the fluid to the place. Instantly the stuff disappeared. “Blamed porous piece of wood,” eyeing me queerly. “Or--do you think it's merely porous, Mr. Fenton?” For answer I took a brush and repeatedly daubed the place. It was like dropping ink on a blotter. The wood sucked up the varnish as a desert might suck up water. “There's about a quart of varnish in the wood already,” observed Johnson, as I stared and pondered. “Suppose we take it down and weigh it?” Inside of a minute we had that piece of trim down from its place. First, I carefully examined the timber framework behind, expecting to see traces of the varnish where, presumably, it had seeped through. There was no sign. Then I inspected the reverse side of the finish, just behind the peculiar spot. I thought I might see a region of wide open pores in the grain of the pine. But the back looked exactly the same as the front, with no difference in the grain at any place. Placing the finish right side up, I proceeded to daub the spot some more. There was no change in the results. At last I took the can, and without stopping, poured a quart and a half of the fluid into that paradoxical little area. “Well I'll be darned!”--very loudly from Johnson. But when I looked up I saw his face was white, and his lips shaking. His nerves were all a-jangle. To give his mind a rest, I sent him for a hatchet. When he came back his face had regained its colour. I directed him to hold the pine upright, while I, with a single stroke, sank the tool into the end of the wood. It split part way. A jerk, and the wood fell in two halves. “Well?” from Johnson, blankly. “Perfectly normal wood, apparently.” I had to admit that it was impossible to distinguish the material which constituted the peculiar spot from that which surrounded it. I sent Johnson after more varnish. Also, I secured several other fluids, including water, milk, ink, and machine oil. And when the painter returned we proceeded with a very thorough test indeed. Presently it became clear that we were dealing with a phenomenon of the Blind Spot. All told, we poured about nine pints of liquid into an area of about twenty square inches; all on the outer surface, for the split side would absorb nothing. And to all appearances we might have continued to pour indefinitely. Ten minutes later I went down into the basement to dispose of some rubbish. (Charlotte didn't know of this defection in our housekeeping.) It was bright sunlight outside. Thanks to the basement windows, I needed no artificial luminant. And when my gaze rested upon the ground directly under the parlour, I saw something there that I most certainly had never noticed before.