THE WILL IN NATURE.
changed every day. A stick fixed upright within six inches of a young convolvulus is sure to be found by the plant. If, after having wound itself for a certain distance round the stick, it is unwound and wound round again in the opposite direction, it will return to its original position or lose its life in the endeavour to do so. Nevertheless, if two such plants grow close to one another without having any stick near enough for them to cling to it, one of them will change the direction of its winding and they will twine round each other. Duhamel placed some Italian beans in a cylinder filled with moist earth; after a little while they began to germinate and naturally sent their plumula upwards in the direction of the light and their radicula downwards into the mould. After a few days the cylinder was turned round to the extent of a quarter of its circumference and the same process was repeated until it had been turned completely round. The beans were then removed from the earth, when it was found that both plumula and radicula had twisted at each turn that had been given, in order to adapt them selves to it, the one endeavouring to rise perpendicularly, the other to descend, so that they had formed a complete spiral. Yet, notwithstanding this natural tendency to descend, when the soil below is too dry, roots will grow upwards in order to reach any moist substance which may be lying higher than themselves."
In Froriep's Memoranda for 1833 (No. 832) there is a short article upon the locomotivity of plants: in poor soil, where good mould lies near at hand, many plants will send out a shoot into the good mould; after a time the original plant then withers, but the offshoot prospers and itself becomes the plant. By means of this process, a plant has been known to climb down from a wall.
In the same periodical (1835, No. 981) is to be found a communication from Professor Daubeny, of Oxford (taken
PHYSIOLOGY
