Is this actively growing and bending region therefore the part of the root which “realizes” that the whole is in a wrong position, and which therefore bends to put it right? To answer this question quite fully would require a great deal of work, but there are three simple experiments which you can do, and which will tell you the most important facts about it. (1)[5] Take a seedling with a fairly long root which has been growing straight down, then very quickly and with a sharp knife or razor, cut off the last 2 mm. of the tip of the root. Lay the seedling on its side on damp sawdust and examine it next day. ~It will not have bent~, even though it has grown in length (~see~ fig. 30, A). [Illustration: Fig. 30. Experiments on the bending of the root tips in Beans. (~See~ description in text.)] [5] It is better to have half a dozen examples for each experiment, for the seedlings do not always act quite quickly and correctly, and from half a dozen you can see the average result. (2) Take another like it and leave it lying on its side for an hour, and then cut off the tip in the same way as in number one, placing it on its side once more. Next day you will find that ~it has bent in the same way as one which had not been cut~ (~see~ fig. 30, B). (3) Take a third, as like the other two as possible, and lay it on its side all night; do not cut it till next day, when it has definitely begun to bend (~see~ fig. 30, C), then quickly cut off the tip, and place it in the upright position (C^1). You will find that ~it continues to grow in the bent form~, the root tip going on to one side. It does not seem to know that it is growing along instead of down. If you keep it in this position for a few days it will then get a new tip and begin to grow downwards in the usual way (~see~ fig. 30, D). Think over the results of these three experiments, and you will see that it is only when the tip of the root is not cut off that the plant seems to “realize” that it is not in the right position. When the tip is removed it does not bend down even when the whole plant is lying horizontally, and in the other case (fig. 30, C^1, D) it will keep on bending even after it has been put in its right position. We noticed that it is not the very tip itself which bends, so that we see that ~the very tip is the part which “feels” what is happening, while the part just behind it grows and bends~ according to the need of the plant. This is a somewhat similar case to what happens when you realize with your brain that you are in danger on the road, and your feet hurry you across.