THE PURIFICATION OF THE BLOOD, ETC. 55 



impulsive movement is not confined to leaves 

 or flowers ; for it is a fact that roots seeking 

 nutriment, by an innate vital force, which we 

 cannot comprehend, and j^et which must depend 

 on the life of irritability, extend themselves in 

 order to plunge into a propitious soil. Dr. 

 Fleming says, " When the roots of a plant, 

 spreading in search of nourishment, meet with 

 interruption in their course, they do not cease 

 to grow, but either attempt to penetrate the 

 opposing body, or to avoid it by changing their 

 course. Thus I have repeatedly seen the root 

 of the Triticum repcns, or couch grass, which 

 had pierced through a potatoe that had 

 obstructed its course ; and everyone knows that 

 the roots of a tree will pass under a stone wall, 

 or ditch, and rise again on the opposite side, 

 and proceed on their original direction." If we 

 understand Dr. Fleming aright, this phenomenon 

 is supposed by him to be under the governance 

 of a species of instinct. We doubt this, how- 

 ever, unless, indeed, his definition of instinct 

 be different from that of common acceptation. 

 It appears to us that the improper, or uncon- 

 genial, and therefore irritating materials ob- 

 structing the roots, merely stimulate them to 

 increased energy, for a root cannot hunt, as 

 a hound or a mole, after its destined source 

 of nutriment. It is stimulated, but has no 

 aim, nor can it have aim, and the perfora- 

 tion of a congenial soil must be merely acci- 

 dental. Does instinct, we may ask, direct the 

 sunflower to turn its yellow disc to the orb of 



