FIG. 



ILLUSTRATIONS ^fc *J> 



PAGE 



i. Transverse section of the leaf Hydrilla ..... 8 



2. The Plant-vessel and the Bubbler . . . . . . 17 



3. The Automatic Recorder for Photosynthesis .... 23 



4. Records of successive evolution of equal volumes of oxygen 



under constant light . . . . . . . . 28 



5. Diagrammatic representation of arrangement for securing differ- 



ent intensities of light . ...... 32 



6. Records showing the periods of physiological adjustment under 



rapid change of light . . . . . . . . 34 



7. Photosynthetic curve under increasing intensity of light . . 35 



8. Photosynthetic curves for identical Hydrilla plant, under sun- 



light and Pointolite . . . . . . . . 43 



9. The tropic curve under the action of light . . . .52 

 10. Maximum response of Mimosa under increasing intensity of 



electric stimulus . . . . . . 53 



ri. Alternating response of Mimosa and of photosynthesis . . 54 



12. Direct and after-effect of light on growth-elongation of Kysoor . 56 



13. Depression of mechanical response of Mimosa under ether and 



gradual recovery on removal of the anaesthetic . . -57 



14. Special plant-vessel for introducing chemical substances without 



mechanical disturbance . . . . . . . 62 



15. Curve showing the effect on photosynthesis of application of 



1 per cent, ether solution ....... 63 



16. Effect of application of o • 01 per cent, solution of formaldehyde 



on photosynthesis . . . . . . . . 64 



17. Curves exhibiting the effect of infinitesimal traces of HN0 3 , 



thyroid gland and formaldehyde on photosynthesis . . 70 



iS. Arrangement for obtaining electric response to light . . . 74 



19. The negative electric response of Musa to light, exhibiting 



the predominant D reaction ...... 76 



20. The ' overshooting ' of the response of Musa in the positive 



direction on the cessation of light . . . . . 76 



21. The positive electric response of Hydrilla .... 78 



22. Effect of variation of temperature on electric response of 



Hydrilla . . . . . . . . . . 79 



23. Arrest of Desmodium pulsations under excess of C0 2 and re- 



newal on removal of thr gas ...... 80 



24. Depression of the electric response of Hydrilla under excess of 



carbon dioxide ......... 80 



25. Cyclic curve showing effect of increasing periods of darkness on 



induction period ........ 86 



26. Successive records showing increasing induction-period with 



increasing duration of previous darkness . . . . 88 



27. Effect of intermittent light on photosynthetic activity . . 92 



