104 Dr.S. B.Schryver. Some Investigations Dealing [Aug. 12, 
position, and the system becomes monophasic. This point is known as the 
“ critical solution temperature.” 
As it has been suggested that solutions of proteins and other hydrophil 
colloids are diphasic systems analogous to that of phenol and water, in which 
the amount of water in one of the phases can vary within wide limits, the 
investigation of the action of salts on this system was of some interest. 
It was found that the addition of salts which lower the surface tension 
decreased the critical temperature of phenol and water. The critical solution 
temperatures, it is true, do not follow the surface tensions with strict. 
accuracy ; 1t must be remembered, however, that these constants have been 
measured at ordinary atmospheric temperatures only, whereas the critical 
solution points are relatively high. Nevertheless, the concordance is 
sufficiently striking. The viscosity in this case plays but little part, as 
there is passage of molecules to and fro from both systems. Furthermore, 
at higher temperatures, the difference of viscosity in different solutions tends 
to rapidly diminish. 
The last series of systems investigated were those of crystalline substances 
in the presence of salt solutions. The action of salts in these cases was 
found to be analogous in nearly every respect to their action in systems 
containing proteins. The salt solutions with low surface tensions possessed 
a greater disaggregating capacity than those of the same series with higher 
surface tensions. The viscosity of the solutions also played the same part. 
In these systems, also, reaction must be considered as taking place at the 
surface of the two phases. Equilibrium will be attained when disaggrega- 
tion takes place at the same rate as reaggregation. The lower the surface 
tension of the solution, the greater the tendency to disaggregate, and the less. 
the tendency to reaggregate; the equilibrium point will be attained with 
a higher concentration of substance in salt solutions of low surface tension 
than in those of high surface tension. The more viscous the solution, the 
sooner will this equilibrium point be attained at the surface of the two 
phases (7.e. the smaller the quantity of solid substance which will have been 
dissolved), owing to the difficulty of the dissolved substances in diffusing from 
the solid phase. 
These results were arrived at by determining the solubility of the five 
following substances in the same salt solutions as were employed in the 
investigations on protein systems—leucine, phenylalanine, caffeine, para- 
toluidine, and benzamide. The solution capacities of the inorganic salts and 
organic salts followed in the same order as their disaggregating action on the 
globulins. Salt solutions with low surface tension, such as sodium benzoate 
and sodium salicylate, dissolved appreciably more than those of high surface 
