CH. r. 



BY THE SURFACE OF THE ROOTS. 



21 



the ends ; though I think that the free growth of 

 trees transplanted with the ball of earth answers it in 

 the negative. So does the growth of potted green- 

 house plants, all the ends of whose roots are cut off. 

 But certainly the answers elicited from the roots of 

 seedlings are most clear and most decisive, and directly 

 in contradiction to the only fact I have ever heard 

 stated in favour of the absorption by the ends of the 

 roots. And this fact, I have no hesitation in asserting, That a 



radish is 



is not a fact. I give, in Eichard's words, what I believe ff^ only by 

 Senebier first asserted : — fallacy. 



' Eoots also extract from the earth the substances 

 which are intended to serve for the growth of the plant. 

 But all parts of the root do not perform this office, it 

 being only by the extremity of their smallest fibres 

 that this absorption takes place. Some say that they 

 are terminated by little ampullse, or spongy bodies, 

 which are more or less tumid ; and others, by a kind 

 of absorbing mouths. Whatever be their structure, it 

 is certain that the office of absorption is performed by 

 these extremities alone. 



' No experiment is more easily made than that by 

 means of which the truth of this fact is undeniably 

 established. If we take a radish or a turnip, and im- 

 merse in water the extremity of the radicle by which 

 it is terminated, it will vegetate and shoot forth leaves. 

 On the contrary, if it be so placed in the water that 

 its lower extremity is not immersed, it gives no sign 

 of development.' 



