74 FORESTRY IN SPAIN. 



making the action of gravity to come into play. If they have 

 not yet resolved the question satisfactorily if there be still 

 awanting the theory which will account for the same force 

 of gravitation causing the root and the stem to take 

 opposite directions the various conjectures manifest at 

 least the power of the human mind, and they are all of 

 them deserving of commendation. 



'More important, doubtless, it would have been to have been 

 able to determine whether vegetables possess the property of 

 selecting the nourishment which suits them, and refusing 

 what would be noxious ; or whether, on the contrary, 

 they absorb all indiscriminately. And great advances in the 

 somewhat complicated art of cultivation would have been 

 made if we had been able to discover whether vegetables 

 excrete at the extremity of their rootlets, and what it is 

 which they excrete. Although it is nearly a century since 

 Brugman submitted to botanists his views on this last point, 

 and although Macaire, Chatin, Meyen, Garreau, Brauwis, 

 Goldman, Sachs, Unger, Walser, and others, have studied 

 the matter judiciously and carefully, we only know after 

 all that the Rotation of Crops of De-Candolle has no certain 

 basis to stand upon, having been followed because it was 

 expounded by so illustrious a master as genius, like the 

 sun, blinds its satellites, and leads them blindly to follow 

 on, without subjecting their procedure to reason. 



'Another problem, however, and that one more difficult 

 to solve, is to determine clearly whether plants have feeling. 

 In presence of the phenomena presented by curious 

 movements, and special attitudes, it is customary to say 

 that these are caused by the irritability of the tissues, but 

 never by sensibility, which is generally repudiated as an 

 absurd hypothesis; but, bear with me if I ask : Where 

 does sensibility terminate, and irritability begin? What 

 are the limits which separate them ? It is an old trick of 

 man to try to cheat himself by the employment of words 

 which do not express ideas explicitly. We may feel assured 



