at the interpretation and discussion we have labored jointly. In
looking over the other's shoulder we have not always agreed, but
we have hoped that each of our compromises will appeal to some
readers without offending others.

The subject matter of the book divides into three parts. Chap-
ters 1 and 2 are introductory, and 3 through 5 present our major
findings. The remainder deal with preliminary findings, sugges-
tions for further research, and the over-all picture. The profes-
sional scientist who, for one reason or another, wishes to scan the
original experimental material in the book will find his need met
by the summaries at the ends of Chapters 3 through 9 (see Table
of Contents).

GERTRUDE R. SCHMEIDLER

R. A. MCCONNELL

September 1957

-viii-