ter
by a cut branch--notwithstanding the fact that he knew the absorption to
depend largely on the leaves. {130b} It may be noticed that Sachs, in
his imbibitional view of water-transport, may be counted a follower of
Hales.

In order to ascertain "whether there was any lateral communication of the
sap and sap vessels, as there is of blood in animals," Hales (p. 121)
made the experiment which has been repeated in modern laboratories,
{130c} _i.e._ cutting a "gap to the pith," and another opposite to it and
a few inches above. This he did on an oak branch six feet long whose
basal end was placed in water. The branch continued to "perspire" for
two days, but gave off only about half the amount of water transpired by
a normal branch. {130d} He does not trouble himself about this
difference, being satisfied of "great quantities of liquor having passed
laterally by the gap."

He is interested in the fact of lateral transmission in connexion with
the experiment of the suspended tree (Fig. 24, p. 126), which is
dependent on the neighbours to which it is grafted for its water supply.
This seems to be one of the results that convinced him that there is a
distribution of food material which cannot be described as circulation of
sap in the sense that was then in vogue.

Hales (p. 143) was one of the first {131a} to make the well-known
experiment--the removal of a ring of bark, with the result that the edge
of bark nearest the base of the branch swells and thickens in a
characteristic manner. He points out that if a number of rings are made
one above the other, the swelling is seen at the lower edge of each
isolated piece of bark, and therefore (p. 143) the swelling must be
attributed "to some other cause than the stoppage of the sap in its
return downwards," because the first gap in the bark should be sufficient
to check the whole of the flowing sap. {131b} He must, in fact have seen
that there is a redistribution of plastic material in each section of
bark.

We now for the moment leave the subject of transpiration and pass on to
that of root-pressure on which Hales is equally illuminating.

His first experiment (_Vegetable Staticks_, p. 100), was with a vine, to
which he attached a vertical pipe made of three lengths of glass-tubing
jointed together. His method is worth notice. He attached the stump to
the manometer with a "stiff cement made of melted Beeswax and Turpentine,
and bound it over with several folds of w