MOVEMENTS RESULTING FROM SHOCK 521 



from foreign plants be placed upon it. Closure of the stigma must thus be of 

 service in excluding foreign pollen. 



Haberlandt (1901) has drawn attention to certain anatomical adaptations 

 both in sensitive stigmas and stamens which are obviously correlated with recep- 

 tion of the stimulus, but we must refer our readers to his own descriptions of 

 these. 



Bibliography to Lecture XL. 



Bert. 1867. Mem. See. des sc. phys. Bordeaux, 1 866. Paris. 



Bert. 1870. Ibid. February. 



Bonnier. 1892. Revue gen. de bot. 4, 513. 



BRtJCKE. 1848. Archiv f. Anatomic u. Physiologie. Ostwald's Klassiker, No. 95. 



BURCK. 1901. Botan. Centrbl. 1902, 89, 645 Review. 



CoRRENS. 1892. Flora, 75, 87. 



DuTROCHET. 1837. Mem. pour servir a I'hist. d. veget. et d. animaux. Paris. 



[Fitting. 1903. Jahrb. f, wiss. Bot. 39, 424.] 



Haberlandt. 1890. Das reizleitende Gewebesystem d. Sinnpflanze. Leipzig. 



Haberlandt. 1901. Sinnesorgane im Pflanzenreich etc. Leipzig. 



Hansgirg. 1890. Botan. Centrbl. 43, 409. 



Hansgirg. 1893. Physiologische und phycophytologischeUntersuchungen. Prag. 



Hilburg. 1 88 1. Unters. aus d. bot. Inst. Tubingen, i, 23. 



Minden. 1901. Flora, 88, 238. 



Oliver. 1887. Ber. d. bot. Gesell. 5, 162. 



Pfeffer. 1873 a. Physiolog. Untersuchungen. Leipzig. 



Pfeffer. 1873 b. Jahrb. f. wiss. Bot. 9, 308. 



Pfeffer. 1890. Plasmahaut etc. Abh. K. Gesell. d. Wiss., 16, 185. Leipzig. 



Rothert. 1894. Cohn's Beitr. z. Biologie, 7, 1. 



LECTURE XLI 



SUMMARY OF PARATONIC MOVEMENTS. AUTONOMOUS 

 MOVEMENTS 



In our very first lecture we drew attention to the fact that it was not 

 possible, off-hand, to recognize movement in all plants. Nevertheless, in so 

 far as we have studied the changes in form and position exhibited by fixed 

 plants, not to speak of the locomotory phenomena seen in non-fixed forms, we 

 are bound to admit that the popular view that plants have no power of movement 

 is entirely erroneous. Careful observation has made us acquainted with abun- 

 dant instances of movement, although these are less noticeable than movements 

 in the animal world, simply because they are not so rapid. Still, from the 

 scientific standpoint, the rapidity of a movement is not the most important of its 

 features ; its nature, its causes, the means by which it is accomplished, and its 

 significance in the organic economy are the points to which our attention is most 

 prominently directed. With regard to most of these points a remarkable parallel 

 has been drawn in recent years between the movements in response to stimulus, 

 described in Lectures XXXIII to XL, and the reflex movements of animals, and 

 when, in Lecture XLIII, we come to consider locomotory directive movements 

 the analogy will become even more remarkable. 



In Lecture XXXIII we termed the various movements hitherto dealt with 

 paratonic, induced, or receptive movements, and contrasted them with autonomous 

 or spontaneous movements, and in that lecture also we briefly pointed out the 

 grounds on which that distinction was based. Before studying autonomous 

 movements more in detail we must endeavour to bring out the contrast more 

 sharply than we have as yet done. 



Movements in response to stimuli arise only as a result of the continuous 



