2 BULLETIN 505, U. S. DEPARTMENT OF AGRICULTURE. 
ration (supplying a minimum of fat) composed of wheat biscuits, 
oranges, sugar, and tea, or coffee if desired, was supplemented by a 
blancmange or cornstarch pudding, in which was incorporated the 
vegetable fat under consideration. 
The test periods were of three days' or nine meals' duration, to 
agree with the experimental conditions under which the animal fats 
were studied, and the following four days formed a rest period in 
which the subjects furnished their own meals, which differed in no 
special way from an ordinary mixed diet. 
Normal young men in good health and moderately active, all of 
whom were medical or dental students, were the subjects of the diges- 
tion experiments. The prescribed routine involved regularity, espe- 
cially with respect to the time for eating, but the subjects were per- 
mitted to exercise in their customary ways and as required in the 
performance of their daily work. In most cases the subjects had 
had previous experience in similar experiments, and all of them proved 
to be careful and trustworthy assistants. 
Weighings were made of the net amounts of food eaten and feces 
excreted, and samples of both food and feces were analyzed to deter- 
mine the percentages of protein, fat, and carbohydrate which were 
actually digested. 
The experimental method followed has been reported in a previous 
bulletin of this series, 1 the analytical methods being those which are 
approved by the Association of Official Agricultural Chemists. 2 
DIGESTION EXPERIMENTS. 
OLIVE OIL. 
Although olive oil has been known from earliest times as a food 
product, exact information regarding the proportion assimilated by 
the body is comparatively limited, its food value having been gen- 
erally discussed with respect to its theoretical energy value, its 
quality, and culinary and table uses. As regards earlier work, a 
five-day experiment with a healthy man was conducted by Berta- 
relli, 3 who tested the digestibility of a mixture of olive and colza oils 
in a basal ration of white bread and meat; the fat was 95.8 per cent 
digested. Moore 4 has reported a number of animal feeding experi- 
ments in which he found that olive oil was assimilated to the extent 
of from 96.7 to 98.7 per cent. In a comparative series of tests he 
noticed that uncooked oils in the food of guinea pigs were somewhat 
less thoroughly available than was the case when the oil was cooked 
with the food. In general all of the vegetable fats studied were 
digested to practically the same extent. 
i U. S. Dept. Agr. Bui. 310 (1915). 
2 U. S. Dept. Agr., Bur. Chem. Bui. 107 (1912), rev. cd. 
3 Riv. Ig. e Sanit. Pub., 9 (1S9S), Nos. 14, pp. 538-545; 15, pp. 570-579. 
* Arkansas Sta. Bui. 78 (1903), pp. 33-41. 
