206 CONCLUDING EEMAKKS. Chap. V. 



though undeveloped, in almost every plant in the 

 vegetable kingdom. 



It has often been vaguely asserted that plants are 

 distinguished from animals by not having the power 

 of movement. It should rather be said that plants 

 acquire and display this power only when it is of some 

 advantage to them ; this being of comparatively rare 

 occurrence, as they are affixed to the ground, and food 

 is brought to them by the air and rain. We see 

 how high in the scale of organization a plant may 

 rise, when we look at one of the more perfect tendril- 

 bearers. It first places its tendrils ready for action, 

 as a polypus places its tentacula. If the tendril be 

 displaced, it is acted on by the force of gravity and 

 rights itself. It is acted on by the light, and bends 

 towards or from it, or disregards it, whichever may be 

 most advantageous. During several days the tendrils 

 or internodes, or both, spontaneously revolve with a 

 steady motion. The tendril strikes some object, and 

 quickly curls round and firmly grasps it. In the 

 course of some hours it contracts into a spire, dragging 

 up the stem, and forming an excellent spring. All 

 movements now cease. By growth the tissues soon 

 become wonderfully strong and durable. The tendril 

 has done its work, and has done it in an admirable 

 manner. 



