hiformation Storage in Nerve Cells 223 



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Fig. 26. Higher power photomicrograph demonstrating the characteristic con- 

 centration of pyronin-positive material along the inner surface of the membrane. 

 The stained material extends far into the dendrite. Note also the appearance of 

 a bilobed nucleus. Methyl green pyronin stain. Magnification x840 (39). 



system were susceptible in a random way to ionic fluxes induced 

 by nerve impulses the ordinary metabolic machinery of the cell 

 would be rapidly undone. This could be avoided only if the nerve 

 cell represented a special case of uncoupling of the DNA-RNA 

 specification system, thus allowing a degree of freedom for the 

 nucleotide sequence in RNA to be influenced by environmental 

 factors. Or alternatively one might assume that only certain pre- 

 selected molecules are available to influence by ionic flux. One 

 may entertain the view that all possible RNA nucleotide sequences 

 and their correspondingly coded proteins are already available 

 within the cell. An incoming pattern of electrical impulses might 

 select or re-orient some of these molecules at the expense of others. 

 Availability of the stored information might be based upon a 

 cellular "recognition" of the same pattern of impulse impingement 



