germinating beans thus treated, and selected out of several specimens to show the gradations in the degrees of curvature. We will now give in detail a series of experiments, and afterwards a summary of the results. Fig. 65. Vicia faba: A, radicle beginning to bend from the attached little square of card; B, bent at a rectangle; C, bent into a circle or loop, with the tip beginning to bend downwards through the action of geotropism. In the first 12 trials, little squares or oblongs of sanded card, 1.8 mm. in length, and 1.5 or only 0.9 mm. in breadth (i.e. .071 of an inch in length and .059 or .035 of an inch in breadth) were fixed with shellac to the tips of the radicles. In the subsequent trials the little squares were only occasionally measured, but were of about the same size. (1.) A young radicle, 4 mm. in length, had a card fixed behind: after 9 h. deflected in the plane in which the bean is flattened, 50° from the perpendicular and from the card, and in opposition to Sachs’ curvature: no change next morning, 23 h. from the time of attachment. (2.) Radicle 5.5 mm. in length, card fixed behind: after 9 h. deflected in the plane of the bean 20° from the perpendicular and from the card, and in opposition to Sachs’ curvature: after 23 h. no change. (3.) Radicle 11 mm. in length, card fixed behind: after 9 h. deflected in the plane of the bean 40° from the perpendicular and from the card, and in opposition to Sachs’ curvature. The tip of the radicle more curved than the upper part, but in the same plane. After 23 h. the extreme tip was slightly bent towards the card; the general curvature of the radicle remaining the same. (4.) Radicle 9 mm. long, card fixed behind and a little laterally: after 9 h. deflected in the plane of the bean only about 7° or 8° from the perpendicular and from the card, in opposition to Sachs’ curvature. There was in addition a slight lateral curvature directed partly from the card. After 23 h. no change. (5.) Radicle 8 mm. long, card affixed almost laterally: after 9 h. deflected 30° from the perpendicular, in the plane of the bean and in opposition to Sachs’ curvature; also deflected in a plane at right angles to the above one, 20° from the perpendicular: after 23 h. no change. (6.) Radicle 9 mm. long, card affixed in front: after 9 h. deflected in the plane of the bean about 40° from the vertical, away from the card and in the direction of Sachs’ curvature. Here therefore we have no evidence of the card being the cause of the deflection, except that a radicle never moves spontaneously, as far as we have seen, as much as 40° in the course of 9 h. After 23 h. no change. (7.) Radicle 7 mm. long, card affixed to the back: after 9 h. the terminal part of the radicle deflected in the plane of the bean 20° from the vertical, away from the card and in opposition to Sachs’ curvature. After 22 h. 30 m. this part of the radicle had become straight.