42 TRANSPLANTING. [CHAP. III. 



These spongioles are exactly of the nature of 

 a sponge ; they expand at the approach of 

 moisture, and when surcharged with it they 

 contract, and thus force it into the fibrous 

 roots, the cellular integument of which dilates 

 to receive it; hence the moisture is forced (by 

 capillary attraction, as it is supposed) into the 

 main roots, and thence into the stem and 

 branches of the plant ; circulating like the 

 blood, and, after it has been elaborated and 

 turned into sap in the leaves, as the blood is 

 changed in its nature in the lungs, dispensing 

 nourishment to every part as it goes along. 



The roots have no pores but those forming 

 the spongioles ; and only the fibrous roots ap- 

 pear to possess the power of alternate dilatation 

 and contraction, which power evidently depends 

 on their cellular tissue being in an entire and 

 healthy state. Thus, it is quite evident that if 

 the spongiole of any fibril be crushed, or even 

 the cellular tissue injured, it can no longer act 

 as a mouth and throat to convey food to the 

 plant. When this is the case, the injured part 

 should be instantly removed; as its elasticity 

 can never be restored, and it is much better for 

 the plant to be forced to throw out a new fibril 

 than to be obliged to carry on its circulation 

 weakly and imperfectly with a diseased one. 

 Whenever a plant is taken up for transplanting, 

 its roots should, therefore, be carefully examined, 

 and all their injured parts cut off, before it is 

 replaced in the ground. Deciduous plants, and 

 particularly trees and shrubs, are generally 

 transplanted when they are without their leaves, 

 because at that season they are in no clanger of 



