The touch sense of the Sundew is developed to such an extent that it can detect the pressure of a human hair one twenty-fifth of an inch long. The tendrils of the Passion Flower attempt to coil up at the slightest contact of the finger and as quickly flatten out upon its removal. The stamens of the Opuntia or Prickly Pear have specialized papillae of touch exactly similar to the papillae of the Hermione Worm. When rubbed by the body of an insect, they transmit an impulse which causes the anthers to let loose a shower of pollen on the intruder. The animal world cannot exhibit a higher sensitiveness to touch than that displayed by the celebrated Venus Fly-Trap. On each side of the leaf midrib stand three sharp little bristles. They are the sense organs controlling the closing of the vegetable spring. Quick must an insect be to escape their vigilance. Sensation and imagery are so closely connected in the human brain that the existence of one would seem to predicate the other. Fortunately, we have very good evidence to indicate the faculty of plant memory, which must necessarily be built up of images of one kind or another. If a plant which is accustomed to folding its leaves together in sleep on the setting of the sun, be placed in a completely dark room, it will continue to decline and elevate its foliage at regular intervals, indicating that it remembers the necessity for rest even with the reminder of outside stimuli lacking. By what faculty do plants become aware of the approach of spring? Only occasionally are they deceived by January thaws, and no matter how unseasonably cold a March may be, they go right ahead with the preparation of April buds and leaves. So accurate is plant knowledge about the seasons that Alpine flowers often bore their way up through long-lingering snow, even developing heat with which to melt the obstruction, when they feel that spring has really come. What gives plants such courage in the face of contradicting elements, if not an accurate sense of the passage of time and therefore the memory of other seasons, which implies imagery?