x Preface 
to regenerate; and it seemed to me, therefore, desirable to 
reéxamine the whole question of adaptation, for might it 
not prove true here, also, that the theory of natural selection 
was inapplicable? This was my starting-point. The results 
of my examination are given in the following pages. 
I am deeply indebted to Professor G. H. Parker and to 
Professor E. G. Conklin for advice and friendly criticism ; 
and in connection with the revision of the proof I am 
under many obligations to Professor Joseph W. Warren 
and to Professor E. A. Andrews. Without their generous 
help I should scarcely have ventured into a field so full of 
pitfalls. 
BRYN MAWR, PENN., June Io, 1903. 
