AMERICAN SCIENCE SERIES 



AN INTRODUCTION 



TO 



GENERAL BIOLOGY 



BY 



WILLIAM T. SEDGWICK, Ph.D. 



i'ro/essor of Biology in the Massachusetts Institute of Technology^ Boston 



AND 



EDMUND B. WILSON, Ph.D. 



Professor of Zoology in Columbia College, New York 



SECOND EDITION, REVISED AND ENLARGED 



NEW YORK 



HENRY HOLT AND COMPANY 



1899 



