52 
TRANSPLANTING. [chap. ill. 
bruised; and they each terminate in a num¬ 
ber of small pores of extraordinary delicacy 
and susceptibility, which act as little sponges 
to imbibe moisture for the use of the plant. 
It is well known that these spongioles are 
the only means which the plant possesses of 
imbibing food, and that if they should be 
all cut off, the plant must provide itself with 
others, or perish for want of nourishment. 
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 sup¬ 
posed, into the main roots, and thence into 
the stem and branches of the plant; circu¬ 
lating like the blood, and after it has been 
elaborated in the leaves, as the blood is 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 dilation 
and contraction, which power evidently de- 
