DIGESTIBILITY OF OILS AND FATS. 6 
slight chances of error through the assumptions made regarding such 
factors as metabolic products and the digestibility of the nutrients 
in the basal diet. The procedure here adopted is believed to give 
as nearly correct results as any with which this office is familiar, and 
since it has been consistently followed in all the experiments in this 
*-\ laboratory, the results can be confidently said to show the relative 
digestibility of the various food materials thus studied. In compar- 
ing the results of studies conducted by one method with those by 
another, due allowance should be made for differences in procedure 
and calculation, and such allowance will frequently be found to lessen 
apparent conflicts or discrepancies in the findings which different 
investigators have obtained from experiments with similar materials. 
The subjects in the present experiments were young men appar- 
ently in normal health, most of them students in a local university. 
They were familiar with this type of work, having served as sub- 
jects in previous experiments, and were entirely trustworthy. Each 
experiment was carried on for three days and included nine mea's. 
The methods for separation of the feces, analyses, etc., were those 
usually followed. 
In each experiment the special fat to be studied was incorporated 
in a cornstarch blanc-mange or pudding. This was eaten along with 
a basal ration which consisted of commercial wheat biscuit, oranges, 
and sugar and which supplied a very small amount of fat in com- 
parison with that in the blanc-mange. Clear tea or coffee was in- 
cluded when desired. 
The reports of the individual experiments are here presented in 
condensed form, but full data are on file in the Office of Home 
^ Economics. 
EXPERIMENTS. 
COD-LIVER OIL. 
Though long and favorably known in medicine, especially in the 
treatment of tuberculosis and other wasting diseases, cod-liver oil has 
had no general use for food purposes. It has, however, entered into 
the diet to some extent, both the cod livers and the oil finding some 
use as food. Dr. Vivia Appleton, who has studied diet in Labrador, 
has stated in personal communications that cod livers are there con- 
sidered a delicacy and she believes them to be a valuable source of 
vitamin A. Fishermen from points north of Boston are said to take 
the crude oil from cod livers and eat it spread on bread. The short- 
age of fat and particularly milk fat, ordinarily the most important 
source of vitamin A in child feeding, led Chick and Dalyell 4 to use 
4 Brit. Med. Jour. No. 3109 (1920), pp. 151-154. 
