924 



LIGHT AND LIFE 



Spettiophotometer, recording action: 

 457 



Spinach chloroplasts, light signals from 

 whole: 341 



State symmetries, and electronic dipole 

 transition selection rules for several 

 heteromolecules: 45 



Stereochemistry of oxidation and reduc- 

 tion: 114 



Systellaspis debilis: 756 



Transition moment integral: 46 

 Triphosphopyridine nucleotide, photo- 

 chemical reduction of: 631 

 Triplet state in fluid solution: 69 

 Triplet state in solution, kinetics of: 71 

 Tyrosine and cresol, polarization spec- 

 tra: 88 

 Tyrosine derivatives, acid quenching of 



fluorescence: 84 

 Tyrosine polarization spectra: 96 



Tetragonia expansa: 492 



Tetralin hydroperoxide, decomposition 

 of: 175 



Tetrahydroporphin: 326 



Tetraphenylchlorin: absorption spectra, 

 322; kinetic analysis of photooxida- 

 tion, 323; quantum yield in photooxi- 

 dation, 323; structural formula of, 321 



Tetraphenylporphin: absorption spectra, 

 322; photoreduction of, 325; structural 

 formula, 321 



Thiobacillus dentrificans: 496 



Thiol pyridine derivatives, absorption 

 spectra of: 152 



Thione absorption band, effect of hydro- 

 gen bonding on: 150 



Thionicotinamide: analogue of DPNH, 

 spectrum of methylated product of, 152; 

 DPN absorption spectra of, 147; DPN, 

 oxidized and reduced, 147; DPNH, 

 suggested structure of, 148; DPNH, 

 spectra of, 149 



Threshold determinations: associated 

 with short-wavelength process, 810; 

 with long-wavelength, 811 

 I FN reduction and oxygen evolution: 

 499 



Vibrational and electronic states, en- 

 vironmental perturbations on: 21 



Vicia faba: 434 



Vision: duplicity theory of, 788; excita- 

 tion by light, 720; intensity factor in, 

 706; photochemical theory of, 711; 

 response to intensity, 709 



Visual excitation: 737 



Visual pigment: relation of absolute 

 threshold to, 715; relation of incre- 

 ment threshold to, 714; in man, meas- 

 urement of, 713 



\'isual sensitivity, photopigment concen- 

 tration and: 740 



Visual systems, molecular organization: 

 724 



\'itamin A deficiency, visual threshold 

 in: 746 



\'itamin A and retinene, geometric 

 isomers: 728 



Vitamin A^: 724 



Zein, polarization spectra: 96 



Zinc tetraplienylporphine cheniiiuiniu- 



escence, decay of: 176 

 Zygaena: 756 



