INTRODUCTION 



To THE 



STUDY OF BIOLOGY. 



BY 



H. ALLEYNE NICHOLSON, 



M. D., D. Sc, M.A., Ph.D., F.R.S. E., F. G. S., etc., 



PROFESSOR OF NATURAL HISTORY AND BOTANY IN UNIVERSITY COLLEGE, TORONTO, 



FOR.'MERLY LECTURER ON NATURAL HISTORY IN THE MEDICAL SCHOOL 



OF EDINBURGH, ETC., ETC.; AUTHOR OF "tEXT-EOOKOF 



GEOLOGY," "text-book OF ZOOLOGY," 



"manual OF ZOOLOGY." 



NEW YORK: 



D. APPLETON AND COMPANY, 



549 & 551 BROADWAY. 



1872. 



f^ 



