THE JOURNAL 
OF 
THE LINNEAN SOCIETY. 
The Effect of — on Turgescent Vegetable Tissues. 
By Anna BarrSoN, Newnham College, Cambridge, and 
Francis Darwin, F.R.S., F.L.S. 
[Read 20th January, 1887.] 
Ir the turgescent pith of a growing shoot is freed from the 
external tissues, it exhibits a sudden increase in length. It also 
exhibits, as is well known, a subsequent increase in length if 
placed in damp air or in water. The latter phenomenon, viz. the 
| increase in length when turgescent pith is placed in water, forms 
the subject of the present paper—a subject which, so far as we 
know, has not been systematically worked out. The chief point 
to which we desire to draw attention is the possibility of accele- 
rating and retarding the rate of increase in length by various 
reagents. We think that this subject is of considerable interest, 
as bearing on some of the problems of growth. In the pith we 
have the essential factor in the act of elongation of a growing 
internode freed from restraint, so that the facts gained by the 
study of the pith may guide us in the study of normal growth. 
We by no means assume that our conclusions drawn from the 
pith-experiments are directly applicable to normal growth, but 
merely that they throw light in an interesting manner on that 
subject. 
LINN. JOURN.— BOTANY, VOL. XXIV. B 
