Often underreported income

Usage examples of tips.

Manner in which radicles bend when they encounter an obstacle in the soil--Vicia faba, tips of radicles highly sensitive to contact and other irritants--Effects of too high a temperature--Power of discriminating between objects attached on opposite sides--tips of secondary radicles sensitive--Pisum, tips of radicles sensitive--Effects of such sensitiveness in overcoming geotropism--Secondary radicles--Phaseolus, tips of radicles hardly sensitive to contact, but highly sensitive to caustic and to the removal of a slice--Tropaeolum--Gossypium--Cucurbita--Raphanus--Aesculus, tip not sensitive to slight contact, highly sensitive to caustic--Quercus, tip highly sensitive to contact--Power of discrimination--Zea, tip highly sensitive, secondary radicles--Sensitiveness of radicles to moist air--Summary of chapter.

The solution was allowed to evaporate, until it became so thick that it set hard in two or three seconds, and it never injured the tissues, even the tips of tender radicles, to which it was applied.

The tips of the radicles were placed so as just to touch the upper end of the glassplates, and, as they grew downwards they pressed lightly, owing to geotropism, on the smoked surfaces, and left tracks of their course.

Aesculus, and the tracks left by the tips of four radicles of the present plant, whilst growing downwards, were photographed as transparent objects.

Moreover, a close examination of almost every one of the tracks clearly showed that the tips in their downward course had alternately pressed with greater or less force on the plates, and had sometimes risen up so as nearly to leave them for short intervals.

In four cases the tracks left were almost straight, but the tips had pressed sometimes with more and sometimes with less force on the glass, as shown by the varying thickness of the tracks and by little bridges of soot left across them.

As the arched hypocotyl grew upwards it tended to draw up the whole seed, and the peg necessarily rubbed against both tips, but did not hold either down.

This was ascertained by measuring the distance between the tips of the cotyledons of four seedlings at midday and at night.

When small drops of the shellac were placed on the tips without any card, they set into hard little beads, and these acted like any other hard object, causing the radicles to bend to the opposite side.

We may therefore infer that any cause which renders the growth of the radicles either slower or more rapid than the normal rate, lessens or annuls the sensibility of their tips to contact.

In ten instances, radicles which had curved away from a square of card or other object attached to their tips, straightened themselves to a certain extent, or even completely, in the course of from one to two days from the time of attachment.

These after being touched with thick gumwater, were placed on the tips of eleven radicles.

Some trials were next made by irritating the tips without any object being left in contact with them.

The tips of two other radicles were rubbed in the same manner for 15 seconds with a little round twig, two others for 30 seconds, and two others for 1 minute, but without any effect being produced.

These results led us to pursue the experiment, and 18 radicles, which had grown vertically downwards in damp air, had one side of their conical tips sliced off with a razor.