DIGESTIBILITY OF OILS AISTD 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 meals. 

 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 wdiich 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 Daly ell* to use 



*Brit. Med. Jour. No. 3109 (1920), pp. 151-154. 



