Wonderful as these facts are, yet they are not more so than some recent discoveries made by Stahl while studying the simple movements and physical conditions of certain low plants called Myxomycetes. In their young stages these plants wander from the parts of the deposit on which they are creeping, and which are gradually drying up, toward those which are more moist. It is possible, by bringing moist bodies in proximity to any ramifications, to produce pseudopodia, which lift themselves from the deposit, and soon come into contact with the moist object, so as to enable the whole mass of the plasmodium, that is, the large, motile, membranous protoplasmic body formed by the coalescence of the swarm-spores of the Myxomycetes, to migrate thereon. But on the entrance of the plasmodia into the fructifying condition, the Myxomycete quits the moist deposit, technically called the substratum, and creeps upwards on to the surface of dry objects. Unequal distribution of warmth in the substratum and unequal supplies of oxygen and chemical substances soluble in water also cause locomotion in these strange organisms. Let the plasmodia come into contact on one side with solutions of saltpetre, carbonate of potash or common salt, and they at once withdraw from the dangerous spot; but an infusion of tan, or a dilute solution of sugar, causes a flow of the protoplasm and an ultimate translocation of the entire plasmodial mass towards the source of nourishment. Some solutions have an attractive or repulsive effect, but this is in accordance with the degree of their concentration. Unlike what is so natural to plants in general, the Myxomycetes seem to have an aversion to light, as shown by their disposition to withdraw from its presence.