23. Twenty-four hours’ record of excitability of _Mimosa_ 59 24. Midday record from noon to 3 P.M. 62 25. Evening record from 6 to 10 P.M. 63 26. Morning record from 8 A.M. to 12 noon 64 27. Diurnal variation of excitability showing marked nyctitropic movement 65 28. Diurnal curves of temperature and of corresponding variation of excitability of _Mimosa_ 68 29. Diurnal variation of excitability of a summer specimen 70 30. The Resonant Recorder 76 31. Variation of excitability after section 80 32. Effect of amputation of upper half of pulvinus of _Mimosa_ 84 33. Response of _Mimosa_ after amputation of lower half of pulvinus 86 34. Effect of weight on rapidity of fall 87 35. Stimulating action of Hydrogen peroxide 88 36. Incomplete recovery under the action of BaCl_{2} and transient restoration under tetanisation 89 37. Antagonistic action of alkali and acid 90 38. Fatigue due to shortening of recovery-period 91 39. Effect of constant current in removal of fatigue 92 40. Stimulating action of light and depressing action of darkness 94 41. Action of glycerine in enhancing speed and intensity of transmitted excitation in _Mimosa_ 102 42. Effect of injury in depressing conductivity in normal specimen 104 43. Effect of injury in enhancing conductivity in a subtonic specimen 105 44. Diagram of experimental arrangement for conductivity control in _Averrhoa bilimbi_ 109 45. Diagram of complete experimental arrangement for conductivity control in _Mimosa pudica_ 116 46. Record showing enhanced velocity in ‘up-hill’ and retarded velocity in ‘down-hill’ transmission 121 47. Direct and after-effect of heterodromous and homodromous currents 124 48. Diagram of experimental arrangement for variation of conductivity of animal nerve 126 49. Effect of heterodromous and homodromous current in inducing variation of conductivity in nerve 127 50. Record of ineffectively transmitted salt-tetanus becoming effective under heterodromous current 129 51. Direct and after-effect of homodromous current 131