86 ION SERIES AND PROTEINS. I 



For cations, Mg < NH4 < K < Na < Li. 



For anions, CNS < I < Br < CI < acetate < tartrate < citrate 

 < phosphate < sulfate < Fl. 



The reader will notice that in the cation series the divalent cation Mg 

 is next to NH4 and K, while we should expect it to follow Li in order of 

 efficiency. On the other hand, if the efficiency of the monovalent, 

 monatomic cations increases in the order of K < Na < Li as Hof- 

 meister and Pauli observed we should expect the efficiency of the 

 anions to increase in the order of CI < Br < I instead of in the re- 

 verse order. We must conclude that the phenomena of precipitation 

 of proteins by ions are either not determined by the electrostatic 

 forces of the ion or that other variables enter which are not yet known. 

 This latter possibility exists since the concentration of electrolytes 

 required for precipitation is very high and the writer has shown that 

 the influence of ions causing the anomalous diffusion of water through 

 membranes already ceases to be noticeable in comparatively low con- 

 centrations of electrolytes.^ 



It therefore seems advisable to restrict our attention to such influ- 

 ences of ions where they act in low concentrations. This is possible 

 when we compare the effects of low concentrations of different acids 

 and alkalies on the physical properties of proteins. The first one who 

 undertook such a study on a larger scale was Pauli. He recognized 

 that in order to investigate the effect of acids and alkalies on proteins 

 it was necessary to free them first from salts. When Pauli and 

 Handovski^ added to blood albumin dialyzed for 6 weeks various quan- 

 tities of different acids they found that all the acids increased the vis- 

 cosity of the blood albumin but in a different degree. Their results 

 are expressed in curves from which we gather that the relative order 

 of efficiency of various acids tried by them was 



HCl > monochloracetic > oxalic > dichloracetic > citric > acetic 

 > sulfuric > trichloracetic acid 



where HCl raises the viscosity most, and trichloracetic least. The 

 -viscosity was measured by the time of outflow through a viscometer. 

 Pauli assumes, as Laqueur and Sackur^ had done previously in their 



4 Loeb, J., /. Gen. Physiol., 1919-20, ii, 173. 



^ Pauli, W., and Handovski, H., Biochem. Z., 1909, xviii, 340. 



^ Laqueur, E., and Sackur, O., Beitr. chem. Physiol, u. Path., 1903, iii, 193. 



