22 SOAPS AND PROTEINS 



show that, in the oleic series also, the soap of the higher fatty 

 acid has a greater absolute gelation capacity than a lower one. 



Because linolic, oleic and stearic acids differ from each other 

 only in the degree of their hydrogenation it is of interest to com- 

 pare the gelation capacities of their three sodium soaps. The 

 amount of water in cc. held per gram of dry soap is as follows: 



Linolic (C, 7 H 3 iCOOH) 3.31 



Oleic (CiTHaaCOOH) 3.28 



Stearic (dvH^COOH) 88.00 



FIGURE 12. 



When comparison is made of the amount of water in cc. held 

 per mol of dry soap, the values are as follows: 



Linolic (Ci 7 H 3 iCOOH) 1,000 



Oleic (C 17 H 33 COOH) 1,000 



Stearic (C 17 H 35 COOH) 26,928 



Or, expressed as percent of soap required to yield the described 

 colloid systems: 



Linolic 23.20 percent 



Oleic 23 . 31 percent 



Stearic 1 . 12 percent 



c. The Effects of Water Concentration. The physical state of a 

 soap/water system has in the above paragraphs been shown to 

 be dependent upon (a) the type of base, and (b) the type of fatty 

 acid in the soap. We wish now to emphasize the fact that a third 

 element in the matter is (c) the concentration of the water. This 

 item, which will be considered in greater detail later because 



