AMINO ACID NEEDS FOR MAINTENANCE

Early in this century, attention of physiologic chemists was turned from a consideration of the quantity of protein required for physiologic well-being to the possible significance of the quality of food proteins. Largely as a consequence of the investigations of Fischer, Hopkins and Osborne and Mendel, the conception became established that for adequate growth certain of the amino acids into which proteins can be degraded through hydrolysis are indispensable, whereas other amino acids can apparently be synthesized by the animal organism itself. Through the more recent studies of Rose and his collaborators the list of these indispensable dietary components has been extended, until now there are ten amino acids recognized as "essential" for the growth of the young of those mammals thus far investigated, provided the rest of the diet is adequate nutritionally. With the generally increasing interest in the welfare of the adult and the aged, attention has been