I dreamed once that I was with a doctor in his surgery, and saw in his hand a note from a patient saying that doctors were fools and did him no good, but he had lately taken some _selvdrolla_, recommended by a friend, and it had done him more good than anything, so please send him some more. I saw the note clearly, not, indeed, being conscious of reading it word by word, but only of its meaning as I looked at it; the one word I actually seemed to see, letter by letter, was the name of the drug, and that changed and fluctuated beneath my vision as I gazed at it, the final impression being _selvdrolla_. The doctor took from a shelf a bottle containing a bright yellow oleaginous fluid, and poured a little out, remarking that it had lately come into favour, especially in uric acid disorders, but was extremely expensive. I expressed my surprise, having never before heard of it. Then, again to my surprise, he poured rather copiously from the bottle on to a plate of food, saying, in explanation, that it was pleasant to take and not dangerous. This was a vivid morning dream, and on awakening I had no difficulty in detecting the source of its various minor details, especially a note received on the previous evening and containing a dubious figure, the precise nature of which I had used my pocket lens to determine. But what was _selvdrolla_, the most vivid element of the dream? I sought vainly among my recent memories, and had almost renounced the search when I recalled a large bottle of salad oil seen on the supper table the previous evening; not, indeed, resembling the dream bottle, but containing a precisely similar fluid. _Selvdrolla_ was evidently a corruption of 'salad oil.' This dream illustrates the uncertainty of dream consciousness, but it also illustrates at the same time the element of certainty in dream _subconsciousness_. Throughout my dream I remained, consciously, in entire ignorance as to the real nature of _selvdrolla_, yet a latent element in consciousness was all the time presenting it to me in ever clearer imagery. We see that the subconscious element of dream life treats the conscious part much as a good-natured teacher treats a child whose lesson is only half learned, giving repeated clues and hints which the stupid child understands only at the last moment, or not at all. It is, indeed, a universal method, the method of Nature with man, throughout the whole of human evolution.