SUBJECT INDEX 



765 



Unimolecular reactions, transmission 



coefficient, 33 

 Unsaturation electrons (7r-electrons), 72, 



73, 89, 90 

 Uranin, fluorescence, 38 

 Urea, 323 

 Urochorda, photosensitivity, 662 



Valence-bond method, 71 



and density alternations, 78, 80 

 Vallisneria, 300 

 Variconjugate sequences, 88 

 Vaucheria, 306 



Vector addition, of orbital angular mo- 

 menta, 99, 100 



of spectroscopic moments, 102 ff. 

 Velocity of light, 130-131 

 Venus, simple photoreceptors only, 638 

 Verbascum, 529, 532 



thapsus, 527 

 Veronica peregrina, 525 

 Vespa, flicker-fusion rate, 649 

 Vibrations, coupling to electronic motion, 

 91 



effect on intensities, 76 



in forbidden transitions, 101 



period, 88 



(See also Double bonds, twist of) 

 Vinylchloroporphyrin-ee from proto- 



pheophytin, 399 

 2-Vinylpheoporphyrin-a5 methyl ester, 

 absorption curve, 405 



structural formula, 400 

 Vinylphosphate, 318, 329 

 Vision, electrical phenomena, 581-619 



temperature coefficient, 34 

 Visual acuity in compound eyes, 658, 669 

 Visual field, in Ebjsia, 640 



in insect ocelli, 646 



in insect ommatidium, 651-652 



in Planaria, 629-630 



Visual field, in Sepia, 642 



Visual identification, 669-670 



Visual pigments, 623 



Vitamin A, 90 



Voltage regulators, 252, 255 



Volucella, detection of polarization plane 



by, 655 

 Volvox, dark and light adaptation, 664 

 photosensitivity, 627-628 



W 



Warburg differential methods, 273 

 Wave functions, 73, 93 



degeneracy and angular momentum, 99 



energies, 74 



even-odd character (parity), 75, 92, 93 



nodes, 72, 74-76 



standing waves, 78 



wave lengths, 74 

 Wave length, definition, 130-131 

 Wave number, 131 

 Weak transitions (see Forbiddenness) 

 Weber-Fechner la\v, 464 

 Width of absorption bands, 76, 87, 88 



effect of substituents, 87 

 Wien displacement law, 150 

 Wigner spin-conversion rule, 14 

 Winkler method, 266 



X 



Xanthium, 541 

 Xenos, aggregated ocelli, 646 

 Xiphosurans, compoimd eyes, 646, 656 

 {See also Limulus) 



Z 



Zea mays, 368 

 Zero-energv orbitals, 93 

 Zinc, 322 

 Zymase, 540 



