We were enabled to trace the movement of another straightening shoot for a longer period (owing to its slower growth and to its having been placed further from the vertical glass), namely, from the early morning on July 13th to late in the evening of the 16th.  During the whole daytime of the 14th, the hook straightened itself very little, but zigzagged and plainly circumnutated about nearly the same spot.  By the 16th it had become nearly straight, and the tracing was no longer accurate, yet it was manifest that there was still a considerable amount of movement both up and down and laterally; for the crown whilst continuing to straighten itself occasionally became for a short time more curved, causing the filament to descend twice during the day.

Smithia Pfundii.—­The stiff terminal shoots of this Leguminous water-plant from Africa project so as to make a rectangle with the stem below; but this occurs only when the plants are growing vigorously, for when kept in a cool place, the summits of the stems become straight, as they likewise did at the close of the growing season.  The direction of the rectangularly bent part is independent of the chief source of light.  But from observing the effects of placing plants in the dark, in which case several shoots became in two or three days upright or nearly upright, and when brought back into the light again became rectangularly curved, we believe that the bending is in part due to apheliotropism, apparently somewhat opposed by apogeotropism.  On the other hand, from observing the effects of tying a shoot downwards, so that the rectangle faced upwards, we are led to believe that the curvature is partly due to epinasty.  As the rectangularly bent portion of an upright stem grows older, the lower part straightens itself; and this is effected through hyponasty.  He who has read Sachs’ recent Essay on the vertical [page 276] and inclined positions of the parts of plants* will see how difficult a subject this is, and will feel no surprise at our expressing ourselves doubtfully in this and other such cases.

A plant, 20 inches in height, was secured to a stick close beneath the curved summit, which formed rather less than a rectangle with the stem below.  The shoot pointed away from the observer; and a glass filament pointing towards the vertical glass on which the tracing was made, was fixed to the convex surface of the curved portion.  Therefore the descending lines in the figure represent the straightening of the curved portion as it grew older.  The tracing (Fig. 123, p. 274) was begun at 9 A.M. on July 10th; the filament at first moved but little in a zigzag line, but at 2 P.M. it began rising and continued to do so till 9 P.M.; and this proves that the terminal portion was being more bent downwards.  After 9 P.M. on the 10th an opposite movement commenced, and the curved portion began to straighten itself, and this continued till 11.10 A.M. on the 12th, but was interrupted by some small oscillations and zigzags, showing movement