81 



In phosphorescent dyes we have an indicator for the disturb- 

 ance of water structures and our problem here is to demonstrate 

 with their help that Na actually causes a disturbance which would 

 be incompatible with life if £* played a major role in it and 

 were dependent on order. Different dyes have a different sensi- 

 tivit}' to disorder which declares itself in the length of the life- 

 time of their excitation. A longer lifetime indicates a greater 

 stability and thus a smaller sensitivity. Riboflavine has a short life- 

 time, of the order of 10 "^ seconds, and is thus most sensitive. The 

 lifetime is somewhat longer in rhodamin B, and the longest in 

 acridine orange. 



The excitations, on the whole, are less sensitive to the qualities 

 of the anions than to the qualities of the cations present. So the 

 behavior of rhodamin, on excitation, depends only to a small 

 extent on the nature of the anion and is dominated by that of the 

 cation present.^ 



The behavior of excited rhodamin in the presence of varied 

 concentrations of NaCl, KCl, and Cs and RbCl is shown in Fig. 

 22. The ordinate shows the intensity of phosphorescent light emis- 

 sion in an arbitrary scale, as observed visually. A frozen watery 

 rhodamin solution (10"^ Ai) shows a weak light emission and a 

 disturbance may declare itself in a quenching of this phospho- 

 rescence or in its increase. 



As the middle curve shows, KCl, up to the limits of its phy- 

 siological concentrations (0.16 Al), causes no disturbance and 

 quenches only above the limits of physiological concentrations. At 

 a very low concentration, below 10"- Al. a slight increase in light 

 emission is seen which (as judged by results on riboflavine) 

 might be due to the CI anion. In contrast to this Na" causes a 

 strong disturbance. The difference between Na" and K~ can most 

 convincingly be demonstrated by holding, side by side under the 



^ The difference in the action of the various halogens can be demonstrated 

 in more sensitive dyes such as riboflavine, v/hich behaves differently in tlie 

 presence of KF, KCl. KBr, and KI. 



