Nov. 24, 1923 
Studies on Rancidity 
355 
sorption in curve C is slightly different from that in curves A and B, this 
difference is nevertheless within the limit of experimental error, so that 
even from this experiment it is extremely probable that the phloroglucid 
from rancid fats is identical with that obtained from substance K and 
from epihydrin aldehyde diethylacetal. 
The results obtained from the examination of the weakly acid aqueous 
solutions of the phloroglucids prepared from epihydrin aldehyde diethyl¬ 
acetal and rancid lard, respectively, are plotted graphically in figure 2. 
The change in solvent was made in the interest of obtaining optically 
clear solutions and has been accompanied by a slight shift in the location 
Fig. 2.—Absorption curves of weakly acid aqueous solutions of phloroglucin condensation products ob¬ 
tained from (D) epihydrin aldehyde diethylacetal, and (E) rancid lard. Curve F is obtained by scaling 
down curve D. 
of the point of maximum absorption for the phloroglucid of epihydrin 
aldehyde. While the location of the points of maximum absorption in 
curves D and E is identical, the curves indicate a wide difference in inten¬ 
sity of color between the solutions from which they were derived. Curve 
F was therefore prepared by scaling down curve D, in the manner already 
described, and is seen to be practically identical in all respects to curve E. 
Since the colors in both cases are known to belong to the same class of 
dyestuffs and to be dissolved in the same solvent, this affords final proof, 
as far as such proof can be obtained, of the identity of the phloroglucids 
derived from rancid lard and from epihydrin aldehyde, respectively. 
60379—24 - 3 
