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 age in rice or cornmeal. Forgetting for the moment the fat—or oil—content of the pecan which is forty to fifty times as great in percentage as in any of these cereals, making the pecan a balanced food, let us study briefly the nature of the proteins and their availability.

There are in natural protein foods certain acids, called amino acids, which the human system requires in the manufacture of muscle tissues for growth and replacement. There are forty of these amino acids in existence, of which eighteen are essential to the human system, and the pecan con- tains those most essential of the entire forty. It is important to note that Douvel, Menaul and Cajori have found the pecan nut of high nutritive value because of its proper type of protein content. The results of their experiments agree in showing the protein of the pecan to be of very choice char- acter; and confirm the experience of earlier inves- tigators who referred to the protein of nuts as vegetable casein because it so closely resembled the protein of milk in character.

Among the amino acids most largely present in the protein of pecans are those very important ones, tyrosin, tryptophane and histidine.

Trytophane is one of those essential consti- tuents of body tissues which the human system cannot manufacture, and which therefore must be found in the food we eat—hence the importance of the pecan as a source of this important amino acid.