446 PROTOPLASM 



same series to hold for the precipitation of lecithin. Pauli gives 

 a similar series based on the influence of acids on the viscosity 

 of albumin from blood: Hydrochloric > monochloracetic > 

 oxalic > dichloracetic > citric > acetic > sulphuric > trichlorace- 

 tic. The strong monobasic (monobasic, dibasic, etc., express 

 the valence of the anion of the acid) hydrochloric acid increases 

 the viscosity of blood most. It is followed by the weak mono- 

 chloracetic acid, and this by the dibasic oxalic. Later comes the 

 weak tribasic citric acid, which is followed by the weak mono- 

 basic acetic, and this in turn by the strong dibasic sulphuric, which 

 joins another monobasic acid, trichloracetic. The series shows 

 no relationship to valence. 



Jacques Loeb, antagonist of colloidal phenomena which appear 

 to run counter to classical physicochemical rules as do theHof- 

 meister series, flatly denied the existence of such series. He 

 stated that they are purely fictitious and due to a failure to 

 measure the acidity of the solutions. The effect, Loeb main- 

 tained, is the result of a change in acidity which the ions produce; 

 that is to say, an ion is effective within its valence group only in 

 so far as it alters the acidity of a solution. If the solutions are 

 all brought to the same acidity value, the effects of the ions will 

 be of four degrees only, caused by mono-, di-, tri-, and quatra- 

 valent ions. Loeb then proceeded to prove this. He took a 

 typical Hofmeister series, such as is claimed to show the relative 

 effects of anions on the osmotic pressure, swelling, and viscosity 

 of protein solutions : SO4 < acetate < CI < Br, NOs < I < CNS. 

 The particular property that Loeb measured was the potential 

 at the surface of a collodion membrane. He used sodium salts 

 of all of the anions in the above series and found that if the 

 solutions are kept at the same acidity value, the anions each 

 produce quantitatively the same depressing effect on the mem- 

 brane potential, except for sulphate, which is the only bivalent 

 anion in the group. (The depressing effect of sodium sulphate is 

 much greater.) It must be admitted that there is some truth in 

 Loeb's argument. His experiments reduce the Hofmeister series 

 simply to quatravalent > trivalent > bivalent > monovalent 

 ions. 



It is certainly true that large valence effects overcome lyotropic 

 ones; most of the latter are within a valence group; but, while 

 acidity is a significant factor in protein solutions, this is not true 



