154 VPS AND PROTEINS 



It is possible to test out these Amoral notions by using the 

 potassium soaps instead of the sodium soaps of the acetic acid 

 series. The potassium soaps being in general more soluble in 

 water and more nearly liquid at a given temperature than the 

 corresponding sodium soaps, permanent eniulsificat ion requires 

 either (a) a higher concentration of the potassium soap or (6) 

 a lower temperature or (r) a soap higher in the series. It there- 

 fore requires more of a soap low in the series like potassium capry- 

 late or caprate to the unit volume of water to yield a permanent 

 emulsion. The emulsions so produced also break easily upon 

 slight increase in temporal ure. ( >n i he other hand, the potassium 

 soaps of the higher fatly acids, which in the presence of water 

 yield more liquid systems even at ordinary temperatures than the 

 corresponding sodium soaps, may be used to obtain permanent 

 emulsions when the corresponding sodium soaps will not act. 

 Potassium laurate, myristate or palmitate mixtures with water 

 act as splendid emulsifying agents at low temperatures at which 

 the corresponding sodium soaps are useless. Even potassium 

 palmitate acts well when the temperature at which it is used 

 lies but slightly above the ordinary room temperature. This 

 is illustrated in the left-hand bottle of Fig. 90. The potassium 

 soaps being more readily soluble in water than the corresponding 

 sodium soaps with increase in temperature, the fine emulsion 

 produced in hydrated potassium palmitate cracks as soon as the 

 temperature is raised to that of a boiling water bath. This is 

 shown in the right-hand bottle of Fig. 90. In this experiment 

 also, 60 cc. cottonseed oil were emulsified in 20 cc. m/16 potassium 

 palmitate by grinding in a mortar. 



3. On the Theory of Foaming and Emulsification 



While we have no direct interest in theories of foaming and 

 emulsification, it is difficult to work in these fields without inquir- 

 ing into the nature of the conditions which make foaming and 

 emulsification possible. 



It would seem from the experiments which have been detailed 

 above and in our previous publications on emulsification that 

 permanent foaming or emulsification is possible only as the liquid 

 into which a gas or a second liquid is dispersed is changed from 

 one possessed of the physico-chemical constants of the pure dis- 



