HANS H. USSING 



during active transport of Na the outflux is only a minute fraction of the influx. If 

 intercellular spaces were important, the outflux would be considerable. 



J. F. Danielli. It is suggested that the surface of Beggiatoa mirabilis has pores of a dia- 

 meter slightly less than that of the sucrose molecule. 



W. G. B. Casselman. Recalling the influence of the neurohypophysial hormone on 

 renal tubercules, have your experiments on frog skin provided any evidence of 

 differential changes of permeability? 



H. Ussing. Neurohypophysial hormone increases the active transport of sodium ions 

 very appreciably, apparently by lowering the resistance to this ion. On the other 

 hand permeability to the chloride ion is only slightly affected. 



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