A TEXT-BOOK 



OF 



PHYSIOLOGY 



FOR 



MEDICAL STUDENTS AND PHYSICIANS 



BY 

 WILLIAM H. HOWELL, PH.D., M. D., Sc. D., LL.D. 



PROFESSOR OF PHYSIOLOGY IN THE JOHNS HOPKINS UNIVERSITY, BALTIMORE 



Siitb je&ition, aborougblE IRevisefc 



PHILADELPHIA AND LONDON 



W. B. SAUNDERS COMPANY 



1915 



