Abstract
1. The surface tension of a glycocholate solution is or is not influenced by the addition of a protein, according to the hydrogenion concentration of the solution.
2. Only at a H-ion concentration of the solution where a protein exists as cation does the presenceof the protein influence the surface activity of the glycocholate solution. The change of the surface activity is caused by the combination of protein with glycocholic acid.
3. The combination of protein with glycocholic acid shows a stoichiometric relation.
4. In this work an explanation is given for the phenomenon that the addition of protein to a very weak solution of glycocholate increase the surface activity of the solution, while in case of a more concentrated glycocholate solution the diminution of the surface activity is observed.
The author expresses here his heartiest thanks to Dr. M. Itoi, whose help in determining the surface tension by the Du Noüy method was invaluable.
