Chap. I.] BY THE SURFACE OF THE ROOTS* 
25 
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 absorp¬ 
tion 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 immerse in water the extremity of 
the radicle by which it is terminated, it will ve¬ 
getate and shoot forth leaves. On the contrary, 
if it be so placed in the water that its lower ex¬ 
tremity is not immersed, it gives no sign of de¬ 
velopment/’ 
First, I think I may fairly ask why “ some ” 
say that each root ends in a sponge ? and why 
other some say, in a capillary stoma? In either 
case, have they seen the fact? Have some seen 
one of these bodies at the end of a root ? and the 
other some, the other of these bodies there ? Or 
are these two bodies so precisely alike that one 
cannot be distinguished from the other ? To my 
eye, there is not much resemblance between a 
sponge and a capillary stoma; and any one who 
agrees with me here will, 1 think, also agree that 
in no science except botany would this extraordi¬ 
narily loose mode of stating facts be tolerated. 
These, however, are not the facts which 1 have 
