446 INDEX 



Sulphuretted Hydrogen, effect of. on growth, 48 



Sunlight, supposed ineffectiveness of, 1 39 ; phototropic curvature under, 



181, 182 

 Susceptibility : definition of, 149 : variation of, at different parts of tropic 



curve, 151 



Tactile pits in tendril of Cucurbita, 90 



Temperature and light, diurnal variation, 202-5 



Temperature, optimum and minimum, for growth, 36, 37 ; double optima, 

 389, 390 ; Thermocrescent Curve, 39 ; death-spasm at fatal point, 

 37. 390 ; effect of variation of, in diurnal movement, 230, 237; on 

 autonomous torsion, 388, 434 



Tendril, twining of, 90, 97, 426 ; effect of electric stimulation on growth 

 of, 91 ; of mechanical stimulation on growth of, 93 > oi unilateral 

 stimulation on response of, 94; electric response at proximal and 

 distal sides, 95 ; inhibitory action of stimulus on response of, 98 



Tension, effect of, on growth, 60 



Thermal dawn and thermal noon, 202, 203, 205, 230, 231 ; light noon and 

 thermal noon, 202, 205 



Thermocrescent Curve, 39, 422 



Thermo-geotropism, 246, 429 



Thermograph, 210 



Thermonastic Recorder, 220, 221 



Thermonasty, 216, 429 ; positive and negative types of, 217, 222, 223 



Thermotropism, 179 



Thunbergia, autonomous torsion of : cyclic variation of temperature on, 

 388 ; death-spasm, at fatal temperature, 390 ; effect of feeble and 

 strong electric stimulation on, 395, 397 > oi indirect stimulation on, 



399 ; of mechanical stimulation on, 400 ; of photic stimulation on, 



401 ;' of red and blue light on, 402 ; of geotropic stimulation on, 404 ; 

 of unilateral geotropic stimulation on, 416 ; combined effects of 

 simultaneous unilateral geotropic and photic stimulation on, 418 



Time-Factor, modification of responsive variation of growth by, 30 

 Torsion, autonomous : effect of variation of rate of ascent of sap on, 386, 

 433 ; of change of temperature on, 388, 434 ; of poisonous solution 

 on, 391, 392; of anaesthetics on, 393, 434; of feeble and strong 

 electric stimulation on, 395, 397 ; of indirect stimulation on, 399, 

 403 ; of thermal shock on, 399, 400 ; of mechanical stimulation on, 



400 ; of photic stimulation on, 401, 434 ; of red and blue light on, 



402 ; of geotropic stimulation on, 403, 434 ; diurnal variation of, 



407 

 Torsion, autonomous : laws of modification of, under unilateral stimulation, 



411 ; effect of unilateral stimulation by light on, 409, 412 ; effect of 



unilateral stimulation by gravity on, 414, 415; combined effects of 



geotropic and photic stimulation on, 417, 435 

 Torsion, induction of, under lateral stimulation, 252, 255, 307 ; directive 



action of stimulus on, 253 ; of differential excitability on direction of, 



255 ; laws of torsional response, 256, 411, 435 

 Torsional Balance, comparison of reactions to diverse stimulations by, 257 

 Torsional Recorder, 251, 252, 306, 383, 385 

 Transpiration, diurnal movement in absence of, 246 



