146 
tend in general to inhibit that series of 
changes which may be brought about in soaps 
through a lowering of temperature, the ad- 
dition of alkali, the addition of salt, ete. 
These findings indicate, therefore, that a 
third element in the hydration and dehydra- 
tion of soaps is resident in the kind and con- 
centration of various alkalies, salts or non- 
electrolytes which may be present in the sys- 
tem. f 
Great care is necessary before it is assumed 
that in order to understand the behayior of 
any mixture of soaps it is only necessary to 
compound the behavior of the individual pure 
soaps. The higher fatty acids uniformly 
yield soaps of the highest absolute hydration 
capacity, and yet if mixtures of a higher fatty 
acid soap and one lower in the series are 
prepared at the temperature of boiling water, 
the physical properties of the system on cool- 
ing are dominated by those characteristic of 
the lower fatty acid soaps. A hydrated so- 
dium or potassium stearate, margarate or 
palmitate which at room temperature is ab- 
solutely solid becomes only viscid or remains 
distinetly liquid when small amounts of the 
caprylates, laurates or oleates are mixed with 
the stearate. 
mm 
It must first be pointed out that all the laws 
here emphasized as governing the hydration 
and dehydration of soaps are identical with 
those which govern the hydration and dehydra- 
tion of certain proteins (like the globulins). 
Whatever is the ultimately accepted theory of 
the nature of the action of the elements enum- 
erated above in producing hydration and dehy- 
dration (“precipitation”) in soaps, this will 
also prove to be the accepted one for this class 
of proteins. As the soaps (but not the fatty 
acids) are “soluble” in water so also are the 
alkalinized globulins (but not neutral glob- 
ulin). As low concentrations of the alkali 
metals favor the hydration of soaps, thus also 
do they favor the hydration of globulin; on 
the other hand, as these same salts in higher 
concentrations “salt out” the former, so also 
do they salt out the latter. As the heavy 
metals, whether added as hydroxide or as salt, 
SCIENCE 
[N. S. Von. XLVIII. No. 1232 
yield sparsely hydrated metallic soaps, so also 
do they yield sparsely hydrated globulins. As 
reversion of hydration or dehydration in soaps 
is easy when the salts of the alkali metals are 
involved, becomes increasingly difficult with 
magnesium and calcium compounds and 
proves only partially successful and then only 
after a long time when salts of the heavy 
metals are used, so also are the analogous re- 
versions easy or difficult in the case of the 
globulins. 
IV 
To explain these changes in soaps, in va- 
rious proteins and in living cells which have 
been subjected to similar changes in their sur- 
roundings we turn to the changes which may 
be seen in mutually soluble systems of the type 
phenol-water-salt as studied by Friedlander 
and his followers and as variously considered 
as of importance for an understanding of the 
changes in colloids! by Hardy, Héber, Wolf- 
gang Ostwald and Hatschek. 
Thus, water is soluble in phenol and phenol 
in water; similarly, water is soluble in soap 
and soap in water. The maximum viscosity 
of a phenol-water mixture appears in the crit- 
ical realm when, under changes in surround- 
ings or composition, phenolated water “ sepa- 
rates out” in hydrated phenol or hydrated 
phenol appears in phenolated water. Soaps, 
similarly, show a maximum viscosity when a 
proper hydrated soap is produced in soap 
water or soap water separates out in hydrated 
1 We accept as the correct definition of ‘‘col- 
loid,’’ the dispersion of one material in a second, 
the degree of dispersion being less than that rep- 
resented by the molecular degree of subdivision 
characteristic of ‘‘true’’ solutions. Limiting our- 
selves to the groups of dispersoids represented by 
solid-liquid and liquid-liquid mixtures (those of 
chief interest, biologically) we do not think that 
the former yield always suspensoids and the latter 
emulsoids, but that etther type may result. 
(Liquid) mercury in water or (liquid) oil in 
water yield suspensoids while (solid) ferric hy- 
droxide ‘or erystallized albumin in water yield 
emulsoids. The emulsoids result when each of the 
phases is soluble in the other; the suspensoids 
when not more than one of the phases is soluble 
in the other. 
