Thus we see, in the locomotion of the Myxomycetes, extremely interesting cases of movements due to stimulation. Light, heat, moisture and gravitation are, in general, stimulus-movements, and ultimately all growth depends on stimulus-movement, the most primitive kind of protoplasmic movement. No causes other than those which actuate higher organisms can be discerned to account for this lowest type of organic movement. What form of inorganic energy can be cited of sufficient potency to cause the organism to change, and without regard to gravitation or any known form of attraction or repulsion, its position in obedience to stimuli acting for its self-preservation? There is none. In the Fuligo, or Tan Flower, a most remarkable example of designed movement has been observed. This form will, according to H. J. Carter, in its early amœbula stage, when isolated from the sawdust and chips of wood among which it has been living, adapt itself to the water of a watch-glass, or any other shallow vessel, in which it may happen to be placed. But, if the watch-glass be placed upon the sawdust, then it will make its way over the side of the glass to get to the sawdust. Here is probably shown a sense-perception of the presence and position of the tan-bark, as well as a feeling of desire to go to it. May not this desire have been due to a sense of discomfort induced by the surrounding water, or to the calling up in memory of some superior comfort associated with the tan-bark? Man in his self-complacency thinks that he knows the plants about him. It is true that he has noted their form, their anatomy, their color and their resemblances and differences, but how few have studied them in meadow and woods by the light of a lantern at night or by the silver rays of the moon. One feels on such an occasion as though he had stepped from his threshold upon a foreign soil. Folded leaves and strange sleeping forms will be found to confront you in every direction. Of the nature of the nocturnal movements of plants, as well as their varied and curious attitudes, both in leaves and flowers, much speculation has been rife among botanists. In many flowers the night attitudes have been conclusively shown to have relation solely to their fertilization by insects; but the drooping night attitudes of the leaves were supposed to indicate an aversion to moisture, many plants seemingly verifying the conjecture by the assumption of the same position during rain as in the dew. But when the same pranks were played on a cloudy day or a dewless night, the explanation had to be abandoned. With the clovers, the nocturnal positions of the heads seem to be assumed only in the darkness, and this invariably, dew or no dew, while the leaves appear to revel in the rain, remaining freely open, their chief concern being the protection of the young blossom-clusters.