
541 
hydrate in each 3 cubic centimeters was prepared, and the 
amount required measured with a pipette in each case. 
1c. c. of this solution was equivalent to 0.55 gms, KOH. 
The fats were soponified as follows: Twenty grams of 
the filtered fat were weighed in a beaker of about 500 c.c. 
capacity and 15 c.c. of the potash solution, equivalent to 10 
grams of caustic potash, were added. Ten cubic centi- 
meters of alcohol were also added, to facilitate saponifica- 
tion. Without alcohol, saponification is incomplete, after 
being heated a long time. The fat and alkali are heated 
upon a water bath with frequent stirring till the alcohol 
is completely driven off. About 350 c.c. of water is then 
added to the contents of the beaker, which is kept unon the 
water bath till the soap is all dissolved. The solution is 
made up to 500 c.c. and when cooled to 20°C. the liquid ig 
adjusted to the mark and the viscosity determined. In case 
the fat examined is an animal fat, as oleo-oil or neutral 
lard, the solution formed will be quite viscous when cooled 
and will be turbid, owing to the separation of insoluble 
soaps. The solution of soaps from butter fat are clear 
amber colored when warm, becoming slightly turbid at 
20°C., but not so much so as other animal tats. 
After determining the viscosity of the soap solutions, 5 
c.c. of the potash solution are added, the solution warmed 
to dissolve the precipitate which forms, and after cooling 
to 20°C, the viscosity is again determined. The viscosity 
found in this second trial will be a trifle less than is ob- 
tained when 20 c.c. of the potash solution is used for sapon- 
ifying the fat, or when 5 c.c. are added to the soap solution 
before making up to 500 c.c. This is due to the difference 
in the volume of the solutions. 
Whether the age of butter has any influence upon the 
viscosity of its soaps has not been definitely determined, ag 
this would require a second examination of a sample of 
butter after considerable interval had elapsed. It is, how- 
ever, quite certain that tnere can be no increase of viscosity 
from this cause, as those butters which have shown the 
lowest viscosity have been quite old. 
