THE VISUAL PIGMENTS 



Carp (Cyprinus carpid), 28, 34-36, 

 39^1, 148-150, 163-164, 175, 

 178-179 

 Casein, 98 



Casein, reaction with retinenej, 106 

 Cat, 5, 28, 198, 200, 202 

 Cattle, 48^9, 53, 84, 89, 97, 117, 119- 



120, 136, 144-148, 151-152, 154 

 Cell holder, 20, 66 

 Cell, optical, 14, 20, 66, 86 

 Centropristes striatas (Black sea bass), 



33-34, 36 

 Cetylammonium chloride, 10 

 Chinook salmon {Oncorhynchus tscha- 



wytscha), 35-36 

 Cholate, sodium, 9, 27 

 Choroid, 1-2 



Chlorine-Hydrogen reaction, 64-65 

 Chloroform, effect on retina of, 31 

 /j-Chloromercuribenzoate (PCMB), 



118 

 Chromophore, 63, 83, 91-92, 123 

 Chromoprotein, 91, 96, 123 

 Cihary muscle, 2 

 c«-Peak, 131-134 



c/Vretineneg, 151-152, 154, 179-180 

 cwg-retinenca, 151, 154 

 cis-trans isomerism 

 definition of, 126-127 

 effect of steric hindrance on, 128- 

 129 

 cis-trans isomers 

 differences in properties of, 131- 



132 

 interconversion of, 134-135 

 of the hexatrienes, 128 

 of the polyenes, 128 

 of retinenci, 137-144 

 of vitamin Ai, 135-137 

 Clupea harengus (Herring), 36 

 Cod, 36 

 Cones, 4 

 Cornea, 1 

 Crocodile, 28, 194 

 Crystalline lens, 1 

 CTAB (Cetyltrimethylammonium 



bromide), 9-10 

 CTAC (Cetyltrimethylammonium 



chloride), 9-10 

 Cyanopsin, 152-155, 180 

 and cisx -retineneg, 152 

 and photopsin, 152 

 and the tench, 154 

 and the tortoise, 154 



Cyprinus carpio (Carp), 28, 34-36, 39- 

 41, 148-150, 163-164, 175, 178- 

 179 



Cytochrome, 11, 96 



Deactivation, 64-65 

 Density, optical, 15, 18, 21 

 additivity of, 18 

 definition of, 1 5 



relation of, to light absorbed, 18 

 standard deviations in the measure- 

 ment of, 21 

 Density spectra (see also Absorption 

 spectra), 13-23 

 definition of, 15 

 distinction from absorption spectra 



of, 15-16 

 independence of shape of, on con- 

 centration, 15, 17 

 measurement of, 19-21 

 Deoxycholate, sodium, 9 

 Dextran, 186 

 Difference spectra, 21-23, 29, 158-164, 



169-178 

 Digitonin, 9, 10 

 Dimethylamine, inertness to retinenej, 



106-107 

 Dioptre, 1 



Diphenylpolyenes, the, 101 

 Dismutation of transient orange, 81 

 Dodecamethylene 1:12 diammonium 



dichloride, 10-11 

 Dog, 28 

 Dogfish, smooth {Galeorhinus laevis), 



36 

 Dogfish, spiny (Squalus acanthias), 

 34-37 



Edestin, reaction with retinenci, 106 



Eel {Anguilla rostrata), 35-37 



Egg albumin, reaction with retinenci, 



106 

 Esox lucius (Pike), 28, 39-41, 158-160, 



178-179 

 Esox reticulatus (Pickerel), 34-36, 



40-41 

 Extinction coeflficient, definition of, 83 

 Extinction coefficient, theoretical limit 



of, 82-83 

 Extractants for visual pigments, 9-11 

 Extractants, mode of action of, 10-11 

 Extraction procedures, 11-13 

 Eye, anatomy of, 1-3 

 Eye, aperture of, 3 

 Eye, refractive power of, 1-2 



210 



