APPENDAGES OP THE AXOPHYTE. 43 



M. -Macaire has proved that plants possess the power of 

 excreting by their roots such injurious matters as they may 

 occasionally necessarily meet with in the soil, and absorb 

 from it in the progress of their development under ground. 

 This gentleman took a fibrous-rooted plant, and having sepa- 

 rated its fibres into two sets, he placed one set in a glass con- 

 taining distilled water, and the other in- a solution of acetate 

 of lead. After a few days he found that the fibres dipping into 

 the solution of acetate of lead, had taken up that poison into 

 the plant, but that the same poison had been excreted or 

 thrown out by the other set of fibres into the glass containing 

 distilled water. Fo r on applying sulphuretted hydrogen, the 

 test for the acetate, he found the distilled water was impreg- 

 nated with it. 



In this experiment we see that the poison was forced into 

 the circulatory system of the plant, which induced a self-pre- 

 servative effort on its part analogous to that made in the 

 higher forms of life. All the experiments made on plants 

 with narcotics and other poisons prove that they possess a 

 principle of life analogous to that of animals. 



The roots of plants when developed in the soil, are also 

 clearly designed to fix them in an upright position, so as to 

 prevent them from being overturned by animals, by the force 

 of the winds, or by any other cause. Hence it is that the 

 roots of a tree are always most numerous and strong to wind- 

 ward, or in the direction of the prevailing winds. When the 

 tree is sheltered on every side, there is little lateral extension 

 of its roots, and they naturally develope downwards into the 

 earth. So also the roots of trees growing on the sides of roads 

 or the banks of rivers, will curve into the embankment, and 

 thus prevent the tree from being undermined or washed away. 



