It has long been known that many parts of plants possessed the power of spontaneous motion to a greater or less extent. The late Charles Darwin made some very interesting experiments on this subject. During the past two years I have also made a great many experiments on this subject.

Roots, stems, and leaves bend to all points of the compass successively with a sort of rolling motion, which Darwin calls circumnutation - a bowing around. Roots grown in damp air in the dark will often make a complete coil, and sometimes two or three of them. If a piece of gummed paper be placed on one side of the root tip it becomes unusually excited and begins to coil away from the paper, sometimes tying itself into a knot, and often succeeds in rubbing off the paper.

The root generally turns downwards, no matter in what direction it first protrudes from the seed.

This is not always true, however, in all of the details. In sprouting 400 or more kernels of Indian corn in damp air, I found the direction taken by the root to vary.

During the past summer I tested some 700 kernels of Indian corn in loose soil; some in the cellar, some in the garden. In damp air roots frequently came to the surface of the soil, where they apparently grew just as well as they grew below the surface. In the garden, exposed to the sun, it is not unusual for roots of corn and beans to come to the surface and perish.

I planted some Lima beans with the eye edge uppermost. Many of them came up after a fashion, but they were a good deal confused. They bent around in various directions, and were very interesting to study.

In the garden nine out of twenty-five, over one-third, of the Lima beans planted with the eye uppermost, sent the radical with all the roots out of the ground, when the whole bean perished.

Darwin made a large number of experiments on a great variety of seedling plants, including some trees, and all, without exception, showed motion of the roots, stems and leaves. He placed a young root under a compound microscope, where he could see it move. He sprouted some beans and placed the tips of the roots against a smoked glass to see what kind of tracks they would make. The tips, in their downward course, had alternately pressed with greater or less force on the plates, and had sometimes nearly left them.

As soon as the tip of the radicle protrudes from the seed-coats, it begins to circumnutate, and the whole growing part continues to do so, probably as long as growth continues. When the earth closely surrounds the roots they may, perhaps, be quite prevented from circumnutating. The tendency to circumnutate must aid in finding the places of least resistance in the soil. Geotropism does not give a root force sufficient to penetrate the ground, but merely tells it which course to pursue. The strength of the radicle of a bean is not enough to indentate the thinnest tin foil when placed horizontally with the radicle thrust perpendicularly downwards. The radicle in such cases turns to one side and glides over the tin-foil without making any impression. The growing part does not act like a nail driven into a board, but more like a wedge of wood driven slowly into a crevice.

[This is part of an address before the Michigan State Horticultural Society in December last. - Ed. G. M.]