When we try to describe what is going on in our minds we are immediately forced to use some sort of imagery, ideas made familiar in some other field. So when anybody reads psychological literature nowadays he is sure to come across the phrase "the threshold of consciousness." Here is a simple picture--a two-room house. One is the conscious room, the other is the unconscious room. There is a door between, and when an idea goes from the conscious to the unconscious room it goes over that threshold, and when it goes back it necessarily has to go over that threshold again. Then James has given us that fine figure, "the stream of consciousness." How good it is! Your thoughts and feelings flow on day after day and year after year like a stream. Practical questions arise at once. What sort of a stream of consciousness have I? Is the stream going steadily on, or is it rather like a babbling brook, making a pleasant murmur but with little power? Or like the River Platte, spreading out and disappearing in the sands of stupidity, or like a turgid stream, so muddy that it is almost impossible to see anything beneath the surface? Or is it a strong, clear, on-sweeping current to which new ideals and feelings are contributed day by day, so that as the years go on it becomes a mighty energy to turn the wheels of the world? A very good figure, and we may very well put such questions to ourselves. Professor Cooley, of Michigan, has suggested another figure which I think would sufficiently antagonize Professor Macnaughton if he were here. Let us imagine a room, the walls and ceiling of which are incrusted thickly with incandescent lights. Near the door let us imagine a box containing a lot of switches. You turn on a switch and that immediately lights up a line across that wall, over the ceiling and down the other wall. You can stand there and turn on and off these switches and light up those circuits of electric lights at will. In similar fashion you have brain cells and these brain cells are like incandescent electric lights, the filaments of which connect with one another into circuits of association. When some one turns on a switch, by a visual image, or by an odor, or by a sound, there suddenly lights up in your mind one of these circuits of memory. When you look at the turrets of that beautiful Chateau Laurier, what do you see? Are you not in the valley of the Loire? Can't you see the frowning front of Chinon, the gracious facade of Asay-le-Rideau, the lacelike stairway of Blois, the massive turrets of Amboise? It is a fine thing to have one's mind well-wired, to have the circuits in good condition. A personal question you can put to yourself is "What sort of mental lights have I? Are they four candle power or thirty-two Tungsten? Are my switches in perfect working order, or are my circuits crossed, and fuses melted so that my mind is in semi or complete darkness?" This is a very practical way of