with the skins a portion of the germ is lost. The germ
readily ferments, which is probably the cause of beans producing
flatulence with some individuals during digestion. After the skins are
removed the nutrients are more susceptible to the action of the
digestive fluids. Experiments show that 42 per cent of the protein of
baked skinned beans is soluble in pepsin and pancreatin solutions, while
under similar conditions there is only 3.85 per cent of the protein
soluble from beans baked without removal of the skins.

[Illustration: FIG. 20.--BEANS, RAW AND COOKED. SKINS, WET
AND DRY.]

87. Use of Beans in the Dietary.--There is no vegetable food capable
of furnishing so much protein at such low cost as beans; from a pound
costing five cents about one fifth of a pound of protein and three
fifths of a pound of carbohydrates are obtained. Beans can, to a great
extent, take the place of meats in the dietary. There is more protein in
beans than in beef. Four ounces of uncooked beans or six ounces of baked
beans are as much as can conveniently be combined in the dietary, and
these will furnish a quarter of the protein of the ration. In the case
of active out-of-door laborers over a pound of baked beans per day is
often consumed with impunity.

88. String Beans.--String beans--green beans with pod--contain a large
amount of water, 85 to 88 per cent. The dry matter is rich in protein,
nearly 20 per cent, although in the green beans as eaten, containing 85
per cent water, there is less than 2-1/2 per cent. Lima beans are richer
in protein than string beans, as the green pod is not included. String
beans are valuable both for the nutrients they contain and for the
favorable influence they exert upon the digestibility of other foods.

89. Peas.--In general composition and digestibility, peas are quite
similar to beans. They belong to the same family, Leguminosae, and the
protein of each is similar in quantity and general properties. The
statements made in regard to the composition, digestibility, and use of
beans in the dietary apply with minor modifications to peas. When used
in the preparation of soups, they add appreciable amounts of nutrients.

[Illustration: FIG. 21.--PEA STARCH GRANULES.]

90. Canned Peas.--In order to impart a rich green color, copper
sulphate has been used in the canning of peas. Physiologists differ as
to its effect upon health. While a little may not be particularly
injurious, much interferes with