The present position in the field of facilitated diffusion and selective active transport 



the pore and the insulin-sensitive mechanism at the outer end. If this were so, an 

 explanation would be provided for the insulin effect upon hexokinase action being 

 dependent on the preservation of structure. 



Many other problems — particularly the phenomena of conduction of impulses by 

 excitable cells — need to be considered from the point of view advanced here, but 

 this must await another occasion. 



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