THE VISUAL PIGMENTS 



Reptiles, visual pigments of, 28 

 Retina, 1-5, 7 

 connections of, to brain, 3 

 dark adaptation of, 7-8 

 diagrammatic section of, 4 

 fluorescence of, 26-27 

 removal of, 8-9 

 a- and /3-retinenes, 143 

 Retinene (retinenci) (see also Indicator 



yellow), 30-31, 33, 38, 53-55, 



83-84, 94, 99, 103-118, 120-121, 



123, 137-148, 152, 154, 179-180, 



185 

 aliphatic amino compounds, reac- 

 tions with, 105-108 

 analysis of, 104 

 a secondary photoproduct 



arguments against, 114-118 



arguments for, 109-114 

 'c/5-peak' region of absorption by, 



140 

 density spectra of isomers of, 138 

 density spectrum in chloroform of, 



33 

 2:4 dinitrophenylhydrazone of, 104 

 extinction coefficient of, 83, 94, 139 

 formula of, 103 

 indicator yellow, relation to, 53, 



104-109 

 iodopsin and /50-iodopsin, relation 



to, 152, 154 

 /50-rhodopsin, relation to, 154 

 isomers of, 137-144 

 'loosely-bound', 109-110 

 molecular weight of, 104 

 opsin, reactions with, 144-146 

 oxime, 116 

 spatial formulae for the isomers of, 



139-143 

 stereochemical form of, in bleached 



visual purple, 146-148 

 test for, 31, 38, 100 

 visual purple (rhodopsin), relation 



to, 30-31, 154 

 vitamin Aj aldehyde, identity with, 



103-104 

 vitamin Aj, relation to, 30-31 

 Retinencg 

 all trans, 151 



dJi, 151-152, 154, 179-180 

 mo, 151, 154 

 density spectrum of, in chloroform, 



33 

 isomers of, 150-155 



porphyropsin, relation to, 32 



test for, 32 



vitamin Ag, relation to, 32 

 Retinene methylimine, 105-106, 108 



hydrolysis of, 112-113 

 Retinene oxime, 116 

 Rhodopsin, see visual purple 

 Rhodopsin-porphyropsin theory, 32-37 



appraisal of, 37^1 

 Rods 



distribution of in human retina, 203 



ease of detachment, 12-13 



lipid in, 13 



Safe light, 7 



Salmo fario (Brown trout), 28 



Salmo irideus (Rainbow trout), 36, 



169-171, 178-179 

 Salmon, Chinook {Oncorhyncus tscha- 



wytscha), 35-36 

 Sand flounder {Lophopsetta maculata), 



36 

 Saponin, 9-10 

 Scotopic sensitivity, 6 

 Scotopsin, 154, 179-180 

 Scup {Stenotomous chrysops), 33-34, 36 

 Sea robin (Prionotus carolinus), 33-34, 



36 

 Sehpurpur, 26 



Serine, reaction with retinenci, 106 

 Sheep, 99 



SH- groups, 116, 118 

 ratio to retinenci in visual purple, 



120 

 reagents for, 1 1 8 

 Silver nitrate, titration with visual 



purple, 118-120 

 Soaps as extractants, 9 

 Spectra 

 absorption (see Absorption spectra), 



13-23 

 density (see Density spectra), 13-23 

 diff"erence, 21-23, 29, 158-164, 169- 



178 

 Squalus acanthias (Spiny dogfish), 36 

 Stark-Einstein Equivalence Law, 63 

 Stenotomous chrysops (Scup), 33-34, 36 

 Steric hindrance, 128-130 

 in carotenoids, 130 

 in terphenyl derivatives, 129 

 in vitamin A^, 130 

 Strix fiammia (Owl), 28 

 Sucrose solution for rod suspension, 



12-13 



214 



