336 THANSPLANTING. 



tion of fluid does not take place either by all the surface of 

 their roots, nor even of their fibres, but only by the extremi- 

 ties of the latter, consisting of bundles of vessels surrounded 

 by cellular tissue in a very lax spongy state, whence those 

 extremities are called spongioles. That it is only through the 

 spongioles that absorption to any amount takes place, is 

 easily show^n by growing a plant in water and alternately 

 preventing the action of the spongioles, v/hen languor and a 

 cessation of vital action comes on, and preventing the action 

 of the general surface of the roots, leaving the spongioles 

 at liberty, when the vital energies are immediately renewed. 

 These spongioles are exceedingly delicate in their organi- 

 zation, and a very slight degree of violence destroys them. 

 It is scarcely possible to remove the soil from the roots with- 

 out injuring them in some degree, and if transplantation is 

 effected violently or carelessly, they are in a great measure 

 destroyed. In proportion to the size or age of a tree, is the 

 difficulty of preserving them increased ; and hence, at the 

 same time, the difficulty of transplantation is augmented. If, 

 by any mediod, the spongioles could be preserved unharmed, 

 there wbuld be no reason whatever why the largest forest 

 tree should not be removed as easily as the young plants in 

 a nursery ; but their preservation in such cases is impossi- 

 ble, and therefore the transplantation of trees of great mag- 

 nitude cannot be effected. It is because of the security of 

 the spongioles from injury when the earth is undisturbed, 

 that plants reared in pots are transplanted with so much more 

 success than if taken immediately from the soil. Hence, 

 also, when earth is frozen into a huge ball around the root of 

 a plant, transplantation is effected with the same kind of cer- 

 tainty. The practice of cutting the roots of large trees the 

 year previous to removing them, is attended with success for 

 a similar reason. Wherever the roots are cut through, the 

 new fibres which are emitted, provided a plant is in health, 

 in short tufts, and each terminated by a spongiole, are much 

 more easily taken out of the ground without injury than if 

 they were longer and more scattered among the soil. When 

 destroyed, the spongioles are often speedily replaced, parti- 

 cularly in orchard trees, provided a slight degree of growth 

 continues to be maintained. This is one of the reasons 

 why trees removed in October succeed better than if trans- 

 planted at any other time. The growth of a tree at that 

 season is not quite over; and the first impulse of nature. 



