ize of the larynx, the emotions to which our exterior gives
expression. All are to a certain extent conditioned by the
productivity of our glands of internal secretion." (Llewellys F.
Barker, Johns Hopkins University, 1st President of Association for
Study of Internal Secretions.)

The implications for the statesman, the educator, the vocational
expert, the student of the neurotic and of genius, of delinquents,
deficients and criminals, the explorers of the exceptional and the
commonplace, the understanding of the poetic and kinetic, base and
dull types, as well as of those two master interests of mankind, Sex
and War, are manifest. The mystery of the individual, in all his
distinct uniqueness, begins to be penetrated. And so every phase
of social life, in which the individual is at bottom the final
determinant, must be reviewed in the light of the new knowledge.
History may be examined from an entirely new angle. The biographies
of our Heroes of the Past, in the Carlylean sense, will bear
reinspection. Even Utopias will have to be revised.

The internal secretions constitute and determine much of the inherited
powers of the individual and their development They control physical
and mental growth and all the metabolic processes of fundamental
importance. They dominate all the vital functions during the three
cycles of life. They co-operate in an intimate relationship which may
be compared to an interlocking directorate. A derangement of their
function, causing an insufficiency of them, an excess, or an
abnormality, upsets the entire equilibrium of the body, with
transforming effects upon the mind and the organs. In short, they
control human nature, and whoever controls them, controls human
nature.

The control of the glands of internal secretion waits upon our
knowledge of them, the nature and precise composition of the
substances manufactured by them, and just what they do to the cells.
Envisaging the future, that knowledge today is meagre. Looking back
fifty years, it becomes an amazing achievement and revelation. It is
worth our while to survey the accomplished, and to trace its general
human significance. For a certain tangible degree of knowledge and
control has been attained and should be part of the average citizen's
equipment in dealing with the everyday problems of his life.

THE ATTITUDE OF THE LABORATORY

A certain number of so-called experimental physiologists, that is,
the physiologists of the animal