BIOLOGY 



GENERAL AND MEDICAL 





BY 

 JOSEPH McFARLAND, M. D., Sc. D. 



PROFESSOR OF PATHOLOGY AND BACTERIOLOGY IN THE UNIVERSITY OF 



PENNSYLVANIA; FELLOW OF THE COLLEGE OF PHYSICIANS 



OF PHILADELPHIA, ETC. 



WITH 160 ILLUSTRATIONS 



THIRD EDITION, THOROUGHLY REVISED 



PHILADELPHIA AND LONDON 



W. B. SAUNDERS COMPANY 



1916 



