SOAPS, PROTEIN DERIVATIVES AND TISSUES 223 



water is considered and compared with the analogous system 

 protein/alkali/water. l 



If neutralization is not complete, the result is an emulsion of 

 the uncombined fatty or proteinic acid in such hydrated " soap " 

 as is produced. If neutralization is complete and the water con- 

 tent is sufficiently low, only pure hydrated alkali stearate or 

 hydrated alkali proteinate is obtained. This obviously corre- 

 sponds to the lowermost levels of the two diagrams. Depend- 

 ing upon the temperature either solid (Fig. 49) or liquid (Fig. 48) 

 systems may be obtained. With sufficient water, only a true 

 " solution " of the alkali stearate or alkali proteinate in water is 

 obtained. We are then in the topmost levels of the two diagrams. 

 In such solution, however, there follows hydrolysis of these com- 

 pounds, so that in addition to molecules in solution there may 

 appear, beside the soap, free fatty or proteinic acid and free 

 alkali and along with these the ions of these substances. The 

 presence of such ions in the case of protein/water systems has 

 commonly been called upon to account for their colloid-chemical 

 properties. Things are almost exactly the reverse. The most 

 definitely colloid soap or protein/water systems, in other words 

 the more concentrated ones, are at the other end of the diagrams 

 and show no ions at all. Whenever such appear, they are the 

 accidental products of dilution and hydrolysis. They begin to 

 appear therefore as soon as soap or protein in true solution in 

 water appears within the hydrated soap or protein, in other words 

 in all the various mixed systems which lie in or above the level Y. 

 The ions are, however, not in the hydrated colloid, but in those 

 portions of these mixed systems which contain dissolved, dissoci- 

 ated and hydrolyzed soap or protein. 



To illustrate the infinite variety of systems that may result 

 from mixture of a base with a fatty acid or protein we need but 

 list the following: fatty or proteinic acid emulsified in hydrated 

 soap or basic proteinate, and vice versa; soap or protein " solu- 

 tion " in solid hydrated soap or basic proteinate, and vice versa; 

 soap or protein "solution " in In pud hydrated soap or basic pro- 

 teinate and vice versa; soap or protein " solution," pure and free 

 from ions or such as contains free fatty or proteinic acid, free 

 alkali, and the whole gamut of ions; all determined obviously 



1 Figs. 13 and 76 and Figs. 98 to 103 with the accompanying texts 



should lx- Mtuiliril in tins 



