DIGESTIBILITY OF SOME ANIMAL FATS. 5 
reasonable accuracy. It was not considered necessary to determine 
variations in the body weight of the subjects, as the purpose of the 
investigations was to ascertain the availability to the body of the 
particular fats in question rather than to supply a diet of sufficient 
nutritive and energy value to meet the body needs. All analytical 
determinations were made according to the methods outlined by the 
Association of Official Agricultural Chemists. 1 The resultant data 
only are included in the report of the experiments which follow. The 
dates of the individual tests and all the detailed data not essential 
in interpreting the results are on file at the Department of Agricul- 
ture, where they may be consulted. 
DIGESTION EXPERIMENTS. 
LARD. 
Pork fat is utilized for food in a variety of forms, the most common 
of which are bacon, salt and fresh fat pork, and lard. Lard is used 
principally for frying and for shortening foods, though sometimes 
flavored with sweet herbs and spread on bread, like " drippings." 
In view of the wide use of lard as a food material, it is noteworthy 
that no very extensive study of its digestibility has been found on 
record. 
Rubner 2 determined the digestibility of bacon, making two exper- 
iments in which 100 and 200 grams were eaten daily, and found an 
average digestibility of 87 per cent. This obviously is not a true 
value, since he reports that the feces contained small pieces of bacon 
which had not been disintegrated. 
Work concerning fat resorption by man and animals in patholog- 
ical conditions was carried out by Adler. 3 His study of pork fat 
seemed to warrant the conclusion that in pathological conditions 
cooked bacon was more readily absorbed than raw bacon. 
Grindley et al., 4 in a study of the influence of different methods of 
cooking upon the thoroughness and ease of digestion of meat, have 
reported four experiments with fat fresh pork, the fat of which was 
99.4 per cent digested. 
In a number of tests comparing the digestibility of lard with that 
of some other animal fats, Levites 5 found that lard was somewhat 
less thoroughly assimilated than butter and beef fat, from which he 
concluded that lard possesses a laxative property. 
Moore, 6 in conducting experiments to determine the digestibility 
of some of the more common fats, found that about 97 per cent of 
i U. S. Dept. Agr., Bur. Chem. Bui. 107 (1912). 
2 Ztschr. Biol., 15 (1879), No. 1, pp. 170-174. 
« Ztschr. Klin. Med., 66 (1908), No. 3-4, pp. 302-316. 
4 U. S. Dept. Agr., Office Expt. Stas. Bui. 193 (1907), p. 41. 
s Ztschr. Physiol. Chem., 49 (1906), No. 2-3, pp. 273-285. 
« Arkansas Sta. Bui. 78 (1903), pp. 33-41. 
