CONTENTS Xlli 



obtained with stems, roots, tendrils, petioles, stamens, and styles of 

 ordinary plants — Also in fungi — Responsive contraction in Passiflora, 

 comparable in extent with that in Cynerecc — Longitudinal response in 

 plants modified by the physiological variations due to age, season, and 

 chemical agencies .......... 66 



CHAPTER VII 



RESPONSIVE CURVATURE OF MOLECULARLV ANISOTROPIC 

 ORGAN 



Molecular anisotropy artificially induced by one-sided cooling — Cooled side 

 less responsive— Diffuse stimulation causes concavity of the uncooled, 

 that being relatively the more excitable— Local fatigue diminishes excit- 

 ability — Diffuse stimulation now causes concavity of the unstrained side 

 — Similar anisotropy induced in plagiotropic organs, by unilateral action 

 of light — The lower or shaded side of such organs relatively more excit- 

 able— Diffuse stimulation causes current of response from lower to upper, 

 and also concavity of lower half — Responses of plagiotropic Cucurbita 

 and Convolvulus — Differences in excitabilities of outer and inner surfaces 

 of tubular organ — Complex response due to successive excitations of two 

 antagonistic halves of an anisotropic organ — Response of spiral tendrils 

 by uncurling — Response in certain cases by contraction of the spiral or 

 curling — Writhing movement in spiral tendril under strong stimulation . 82 



CHAPTER VIII 



RELATION BETWEEN STIMULUS AND RESPONSE 



Ineffective stimulus becomes effective by repetition— Two types of response 

 in contractile animal tissues, cardiac and skeletal— Response of cardiac 

 muscle on 'all or none' principle; parallel case in Biophytum — In 

 skeletal muscle, increasing stimulus causes increasing response, which 

 tends to reach a limit — Parallel results in longitudinal and electrical 

 response of plants — Effect of superposition of stimuli — Tetanus . . 94 



PART II.— MODIFICATION OF RESPONSE 

 UNDER VARIOUS CONDITIONS 



CHAPTER IX 



ON THE UNIFORM, FATIGUE, AND STAIRCASE EFFECTS 

 IN RESPONSE 



Uniform response in plants — Staircase effect — Fatigue due to molecular 

 strain — Fatigue in plant-responses — Periodic fatigue — Fatigue under 

 continuous stimulation — Explanation of anomalous erection of leaf of 



