The relation of these rays to ordinary light is thus an interesting question. It is well known that all mediums shun light, and there are sound physiological and psychological reasons for this. Daylight has been found to be more destructive to the success of phenomena than any form of artificial light; moonlight is far better than sunlight. It has lately been shown that light exerts a powerful physical pressure, and is a disruptive agency, destroying protoplasm and many of the lower forms of life. We only have to see the effect of sunlight upon a photographic plate to appreciate its power. The absurdity of assuming that light plays no part in such manifestations--where very delicate, subtle, and little understood forces are in operation--is thus manifest. Still, the fluidic hands emit a light of their own; and the question is, Can this emitted light penetrate solid substances--"matter," as we understand it? As the result of a number of experiments, Dr. Ochorowicz ascertained that, in the majority of cases, these rays, like ultra-violet light, did not penetrate solid substances, as do the X-rays; yet their actinic action was found to be far stronger! Here is a field for long-continued observation and experiment. In thought photography, on the other hand, it has been ascertained that the rays can pass easily through solid matter, like the X-rays. The next question of interest which presented itself for solution was this: To what extent can the fluidic hands change their form, size, and contour at will? Experiments were first tried in the reduction of the size of the hands, upon request. Three plates were prepared and laid in a series upon the table at some distance from the medium. Through the entranced somnambule the "double" was then informed of the experiment, and asked to place its hand upon the three plates in succession, willing on each occasion to make the fluidic hand smaller. This was done. An impression of the same hand was obtained on each plate, but it can be seen that, on each occasion, the hand is smaller in size. This was all accomplished within a few seconds. Of these experiments Dr. Ochorowicz says: "We are therefore justified in arriving at the following conclusions: "1. At first, the double's hand is larger than that of the medium. "2. It tends to decrease in length and general size. "3. The palm of the hand, especially, tends to decrease. "4. Only the little finger remains without appreciable change. "5. The change is that of several millimetres, but not enormous. "6. The fingers of the double tended to close nearer together, as well as become smaller--just as an ordinary hand would probably do."