DEFINITION OF PLANTS. 



To a person accustomed to contemplate only the 

 higher orders of plants and animals, it will appear easy 

 to draw the line of distinction and to point out the char- 

 acteristics of each. To him the criterion of Mirbel 

 will appear as hypothetical as it is really just, and he 

 will never find it necessary to resort to such an expe- 

 dient, to determine whether he is examining the organi- 

 sed remains of animal or vegetable life. But when he 

 descends to the inspection of those inferior orders of 

 beings, in which simplicity of organization is combined 

 with powers of life almost extinguished, he then finds 

 it difficult to determine to which kingdom, those or- 

 gans and that life belong. 



In such cases the resources of modern chemistry 

 have furnished us with an additional guide. The pe- 

 culiar phosphoric odour exhaled during the combustion 

 of animal substances, indicating the presence of nitro* 

 gen, has been rarely detected during the decomposi- 

 tion of vegetables, and we may safely infer the animal 

 nature of those organs by whose combustion it is pro- 

 duced. Plants then are organized and living beings, 

 springing from seeds or gems, and nourished by inor- 

 ganic substances which they absorb from the atmos- 

 phere and the earth. Medicine reveals their healing 

 efficacy— chemistry detects the elements of which they 

 are composed, and agriculture and gardening teach 

 how they may be cultivated with the greatest advan- 

 tage. 



But Botany assumes a more elevated station, and 

 points out to her enquiring followers the great variety 

 of their external forms, the curious arrangement which 

 their internal structure presents, their habits, their 

 history, their mutual relations and natural affinities. 

 4* 



