That this is the correct view may be inferred from the effects of the more powerful stimulus of caustic. The bending from the cauterised side occurred much slower than in the previously described species, and it will perhaps be worth while to give our trials in detail. The seeds germinated in sawdust, and one side of the tips of the radicles were slightly rubbed once with dry nitrate of silver; and after a few minutes were allowed to dip into water. They were subjected to a rather varying temperature, generally between 52° and 58° F. A few cases have not been thought worth recording, in which the whole tip was blackened, or in which the seedling soon became unhealthy. (1.) The radicle was slightly deflected from the cauterised side in one day (i.e. 24 h.); in three days it stood at 60° from the perpendicular; in four days at 90°; on the fifth day it was curved up about 40° above the horizon; so that it had passed through an angle of 130° in the five days, and this was the greatest amount of curvature observed. (2.) In two days radicle slightly deflected; after seven days deflected 69° from the perpendicular and from the cauterised side; after eight days the angle amounted to nearly 90°. (3.) After one day slight deflection, but the cauterised mark was so faint that the same side was again touched with caustic. In four days from the first touch deflection amounted to 78°, which in an additional day increased to 90°. (4.) After two days slight deflection, which during the next three days certainly increased but never became great; the radicle did not grow well and died on the eighth day. (5.) After two days very slight deflection; but this on the fourth day amounted to 56° from the perpendicular and from the cauterised side. (6.) After three days doubtfully, but after four days certainly deflected from the cauterised side. On the fifth day deflection amounted to 45° from the perpendicular, and this on the seventh day increased to about 90°. (7.) After two days slightly deflected; on the third day the deflection amounted to 25° from the perpendicular, and this did not afterwards increase. (8.) After one day deflection distinct; on the third day it amounted to 44°, and on the fourth day to 72° from the perpendicular and the cauterised side. (9.) After two days deflection slight, yet distinct; on the third day the tip was again touched on the same side with caustic and thus killed. (10.) After one day slight deflection, which after six days increased to 50° from the perpendicular and the cauterised side. (11.) After one day decided deflection, which after six days increased to 62° from the perpendicular and from the cauterised side. (12.) After one day slight deflection, which on the second day amounted to 35°, on the fourth day to 50°, and the sixth day to 63° from the perpendicular and the cauterised side.