DISTINCTION BETWEEN ANIMALS AND VEGETABLES. / 



The power of moving some part of themselves by an in- 

 ternal principle has also been believed peculiar to animals. 

 It is not so. Many plants are possessed of the faculty, not 

 only of motion of this kind, but of moving as if with some defi- 

 nite purpose. " The sensitive plant possesses it in an emi- 

 nent degree. The slightest touch makes its leaves suddenly 

 shrink, and together with the branch bend down towards the 

 earth. But the moving plant, or Hedysarum gyrans, fur- 

 nishes the most astonishing example of vegetable motion. It is 

 a native of the East Indies. Its movements are not excited 

 by the contact of external bodies, but solely by the influence 

 of the sun's rays.* Its motions are confined to the leaves, 

 which are supported by long flexible foot-stalks. When the 

 sun shines, the leaves move briskly in every direction. Their 

 general motion, however, is upward and downward. But they 

 not unfrequently turn almost round ; and then, their foot- 

 stalks are evidently twisted. These motions go on incessantly, 

 as long as the heat of the sun continues. But they cease 

 during the night, and when the weather is cold and cloudy. 

 The Dionrea muscipula, or Venus' flytrap, a plant of Carolina, 

 affords another instance of rapid vegetable motion. Its leaves 

 are jointed, and furnished with two rows of strong prickles. 

 Their surfaces are covered with a number of minute glands, 

 which secrete a sweet liquor, and allure the approach of flies. 

 When these parts are touched by the legs of the fly, the two 

 lobes of the leaf instantly rise up, the rows of prickles lock 

 themselves fast together, and squeeze the unwary animal to 

 death. If a straw or pin be introduced between the lobes, 

 the same motions are excited." 



The common barberry (Berberis vulgaris) is another in- 

 stance to the same effect. When its flower is fully expanded, 

 if the inside of one of the filaments of its stamens be just 

 touched by a pin or a straw, it contracts instantly, and throws 

 its anther forward with some force against the stigma. 



" When a seed is sown in a reversed position, the young 

 root turns downward to enter the earth, and the stem bends 

 upward into the air. Confine a young stem to an inclined 

 position, and its extremity will soon assume its former per- 

 pendicular direction." The roots of a tree growing on dry 

 or barren ground, in the neighborhood of that which is moist 

 or fertile, become larger, longer, and more full in that direc- 

 tion, than in any other, as if extending themselves to obtain 



* Sir J. E. Smith asserts that light is not necessary, but that only a warm, stiU 

 atmosphere is required to produce this phenomenon in perfection 



