

APPENDICES. 



on the other hand, the arrest is a permanent- cm* ™nvn™^« ^r i 



, -ii u- l i 1 • -. permanent one, movements of a slow, insensibly progressive character 



tt 4zir ,n ,u consequence of the ?raduai fai1 ia ^— -«-w .2. ^irs 



ch aracter 



APPENDIX G. 



EXPEEIMENTS DEMONSTEATINO THE PEOPAGATION OP THE CONDITIONS 



MOVEM 



GIVING RUE TO 



SYSTEM OF TURGID SIEVE-TUBES. 



AEEAS OP DEAD TISSUE DEVOID OF ANY LIVING PROTOPLASM OH 



- 



Experiment I. 



Mi 



the application of the points of a strongly heated pair of forceps. The higher seared area measure,. 



0-69 



th 



examination showed that in both the 



One leaf arose fa m the 

 portion of the axis between the two seared areas, and several others were situated below the low 



tissues had 



been entirely killed throughout the entire thickness of the axis. 



and 



b 



the 



upper one. After the leaves had completely 



the normal 



position 



seared 



and those 



an open flame was applied to the tips of the terminal pinnules of one of the leaves beneath th 

 lower seared area of the axis, and universal propagation of movements took place; all the leaves 

 on the axis, those beneath the lower seared area, the one between the two 

 beyond the upper one alike showing rapid petiolar depression and pinnuhir elevation. 



Experiment II. — An area 05" in length in the axis of a small pot-plant was thoroughly 6eared 

 with heated forceps. On the following day the seared area wa3 perfectly dead, dry and brown ; but the 

 leaves, both below and above it, were in full, normal, diurnal position. When llame was applied to the 

 tips of the terminal pinnules of a distal pinna on one of the leaves beneath the seared area, complete 

 action occurred in it, and propagation of movements presently followed throughout the entire course of 

 the axis. 



Experiment III. — An axis was thoroughly seared at two points in its course. On the following 

 day all the leaves were in normal, diurnal position. The application of flame to the lips of the 

 terminal pinnules of a distal pinna of one of the leaves beneath the lower seared area was followed by 

 movements extending over all the leaves on the axis, including one arising between the two seared 

 areas. The length of each of the seared areas was about 04b*, and microscopical examination showed 

 that the tissues had been thoroughly kilied throughout the entire thickness of the axis. 



Experiment IV.— A pet-plant, consisting of a single axis bearing six leaves, was thoroughly seared 

 and killed at two points, one situated between the second and third leaves from the base of the axis and 



the other bet 



the third and fourth leaves. After all the leaves had completely recovered the 



normal diurnal position, the tips of a pair of heated forceps were applied to the base of the axis and 

 rapid centiifugal propagation of movements presently occurred in all six leaves. 



V.— A plant was treated in the same way ns that of the preceding experiment. After 



forceps to a 



1 



complete recovery of the normal diurnal position the application of the point 



.point near the base of the axis was followed by complete propagation of movements to all 



along its course, beneath, between, and above the seared areas. 



Such experiments conclusively prove that the propagation of movements along the course of axes is 

 neither dependent on any continuous tracts of living protoplasm, nor on the existence of any continu- 

 ous system of turgid tubes along the course of which sudden fluctuations in pressure may be trans- 



mitted. Tl 



of turgidity in the tissues 



The seared areas, in place of any longer being 



are sites which afford abnormal facilities for the escape of liquid from the tissues, as is clearly indicated 

 by the fact that, unless under conditions of excessive atmospheric humidity, the leaves which are situated 



dly soon begin to indicate the presence of insufficient water-supply by their 



fty 



the maximal diurnal position. The thorough searing of the tissues of the axis just as effectually 



i; 



of sieve-tubes 



the ba 



