789 



about that a greater H-ioii concentration can be tolerated. After 

 the concentration of the sulphate has become 0.02 normal, the curve 

 recedes again and later on makes another bend (to 0.00015 ii. 

 H,SO^, O.J 2 n. K,SOJ, which we may consider due to the H-ions 

 counteracting somewhat the effect of the salt in this portion of 

 the curve. 



The course of the curve for sodium acetate (tig. 2) is in the most 

 acid solutions (from about [H] = 10— "^^ (o |-h] i:= 10 6^) of the same 



1 2 3 V > * 



conc.Ni-iuivki 



9 iO If It 1J IV If Ii 1J 



xqofa 



Fig. 2. 



natnre as that of the curve for K^SO^ in the most acid solutions. 

 It was not possible to indicate this H -ion concentration for the place, 

 where the curve reaches the ordinale-axis. In so far as the curve 

 has been indicated in this portion, we likewise see two bends; the 

 first is caused by small quantities of acetate connteiacting the effect 

 of the H-ions, while the second is again brought about by the 

 H-ions diminishing the effect of the salt. 



That the influence of base and of salt was approximately additive, 

 while acid and salt interfere with each other's action, is an impor- 

 tant phenomenon. 



The same phenomenon was observed by Hardy ^) in flocculation 

 and solution of globulins in acid and alkaline salt solutions. The 

 globulins form colloidal solutions, which in theii- behaviour towards 

 acids and bases, must be reckoned among the emulsoids. For they 

 are colloids, which are [)ositively charged in acid and negatively in 

 alkaline solution, because they are ampholytes, i.e. substances which 

 behave both as acids and as bases. 



1) W. B. Hardy, Journ. of Physiol, Vol. XXXIII, 1905—06. 



