THE COLLOID-CHEMISTRY OF SOAPS 9 



II 



THE SYSTEM SOAP/WATER 

 1. Introduction 



In the course of our work on the stabilization of emulsions l 

 i in which we showed that the maintenance of a water-in-oil type 

 nf emulsion is dependent, in the main, upon the substitution of a 

 colloid hydrate for the pure water) we were struck by the fact 

 -that no detailed figures are available which discuss in any syste- 

 matic fashion the absolute hydration or gelation capacities of 

 various pure soaps. Even though many studies 2 on the chem- 

 istry of soaps and their general colloid behavior are available, 

 and even though we possess much empiric knowledge regarding 

 the water content of various commercial soaps, these investiga- 

 tions deal, for the most part, with mixed soaps, with soaps pre- 

 pared in alcoholic solution or with such as have been " salted- 

 out." But, as will be shown in this and subsequent sections, all 

 these circumstances may materially modify the water-holding 

 powers of the involved pure soaps, so that we found it necessary 

 for our own purposes to prepare pure soaps with such factors elimi- 

 nated. Since the values which we have obtained are not only of 

 direct chemical and technological interest l but form the basis for 

 theoretical views covering the nature of the lyophilic colloid state 

 and the behavior of living organisms which are composed of such 

 materials, 3 we give below our detailed findings. First to be dis- 

 cussed is the system composed of pure soap plus water. 



1 MARTIN H. FISCHER and MARIAN O. HOOKER: Science, 43, 468 (1916); 

 Kolloid-Zeitechr., 18, 129 (1916); ibid., 18, 242 (1916); Fate and 

 Degeneration, 29, New York (1917). 



Sec for example F. HOFMEIBTER: Arch. f. exp. Path. u. Pharm., tt, 6 

 (1888); F. KRAFFTan*! II WKILOW: Ber. d. <1< ut < )> m. Geoelbch., S8, 2573 

 (1895); F. MKRKLEN: fctude tmr l:i n-titiiti.in dea aavona du commerce, 

 Marseille* (190t> 1 < -LDBCHMIDT: Kolloid-Zeitechr., , 193, 227 (1908); 

 J LEIMDORFEK: K..ll,,i,l--hem. Bcih. ft. 'J (1911); F. BOTAUI and 



C. VICTOROW: K..11..I.1-X. -it-rlir., 8, 220 (1911), accessible only aa review; 

 W. BACHMANN K,llMi.l./.-itM- ir . 11. li:. 1913 I-'. GOLDBCHMIDT and 

 L. WBIMMANN: K..ll....l-/.-,t.s<-hr , 12. 18(1913); -I I., u K..XMTSCH: Oils, 

 FaU and Wax. 1, 299, London (1915). 



See page 64; also MARTIN H. FISCHER and MARIAN O. HOOKER: 

 Science, 48, 143 (1918); MARTI II 1 IHCHER: (Edema and Nephritis, 3rd 

 New York (1920) 



