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Scientific Memoirs by

TABLE III.—Showing Results of section of Distal Pinnules after a continuous
period of heavy Rainfall— continued.

No. of
Experi-
ment.		 Result.
3 Action in the cut pinnules; long pause; action in the primary pulvinus; long
     pause; very slow, imperfect action in the distal two-thirds of the cut pinna;
     no further result.
4 Action in the cut pinnules; long pause; very slow, incomplete action in the dis-
     tal two-thirds of the cut pinna; pause; action in one pinnule below; no fur-
     ther result.
5 Action in the cut pinnules; long pause; action in the primary pulvinus; pause;
     slow, incomplete action in the distal three-fourths of the cut pinna; no fur-
     ther result.
6 Action in the cut pinnules; long pause; action in the primary pulvinus, but de-
     pression somewhat obstructed; slow, incomplete, centripetal action throughout
     the cut pinna, and partial, very imperfect centrifugal action in one other pinna.
7 Action in the cut pinnules; long pause; action in the primary pulvinus; almost
     complete action in the cut pinna; slight, very imperfect action in one other
     pinna a little above the base.
8 Action in the cut pinnules; pause; action in the primary pulvinus, and full de-
     pression; long pause; very slow, imperfect action in the distal three-fourths
     of the cut pinna; long pause; imperfect action of the basal pinnules of one
     side of the cut pinna; no further result.
9 Action in the cut pinnules; long pause; action in the primary pulvinus; long
     pause; very slow, very imperfect action in the cut pinna and in one other
     pinna; no further result.
10 Action in the cut pinnules; long pause; very slow and exceedingly imperfect action
     in the distal two-thirds of the cut pinna; slow action in the primary pulvinus,
     and full depression; very imperfect action in the basal third of the cut pinna,
     and very slow, very imperfect action in one other pinna; no further result.

       The phenomena presented in this series of experiments are just what ought
to have occurred according to the view that alterations in fluid tension, and the
degree of strain present in various parts in maintaining the expanded condition,
are the essential determinants of the propagation of movements from one part
to another of the plant. The plants were very moist, the supply of root mois-
ture excessive, the atmospheric humidity high, and the leaves loaded with ad-
herent water. Coinciding with these conditions there was very slow, imperfect,
and limited action, and a great tendency to early action on the part of the
primary pulvinus, action in it occurring in 7 out of the 10 cases as the first
phenomenon after action in the cut pinnules.