THE HOMOGENEITY OF VISUAL PIGMENT SOLUTIONS 



maximal (density loss at 470 m//, 0-003). The solution was therefore 

 exposed to white light for 15 min. This caused considerable further 

 bleaching, maximal at 470 m^ (density loss 0-026). The changes in 



0-08 



I I I I : 1 I I I I I I I I I I I 



T 1 I I r 



I I I 1 I I I I I TT 



1 I I I I I 



■'■■''■'' 



400 



600 



700 



500 

 Wave-length (m^u.) 



Fig. 6.2. The two light-sensitive components in tench extracts. •, 

 changes on exposure to white light ('total') ; + , changes on exposure of 

 another sample of the same extract to light of wavelength 610 mpi 

 ('red-sensitive') ; x , further changes on exposure to short-wave light 

 ('red-insensitive') ; O , algebraic sum of red-sensitive and red-insensitive 

 components. pH 8-66, T = 20°C. 

 (Dartnall, 1952a) 



density due to the exposures to green and white light are given by the 

 curve marked 'red-insensitive' in Fig. 6.2. The algebraic sum of the 

 difference spectra of the red-sensitive and red-insensitive components 

 of the extract is also shown in Fig. 6.2, and is in good agreement with 



161 



