PEEF AC E. 



IN preparing this text-book for the use of students and practitioners of 

 medicine, I have endeavored to adapt it to the wants of the profession, as 

 they have appeared to me after a considerable experience as a public teacher 

 of human physiology. My large treatise in five volumes is here condensed, 

 and I have omitted bibliographical citations and matters of purely historical 

 interest. Many subjects, which were considered rather elaborately in my 

 larger work, are here presented in a much more concise form. I have 

 added, also, numerous illustrations, which I hope may lighten the labors of 

 the student. A few of these are original, but by far the greatest part has 

 been selected from reliable authorities. I have thought it not without 

 historical interest to reproduce exactly some of the classical engravings 

 from the works of great discoverers,, such as illustrations contained in the 

 original editions of Fabricius, Harvey, and Asellius. In addition, I have 

 reproduced a few of the beautiful microscopical photographs taken at the 

 United States Army Medical Museum, under the direction of Dr. J. J. 

 Woodward, to whom I here express my grateful acknowledgments. I have 

 also to thank M. Sappey for his kindness in furnishing electrotypes of many 

 of the superb engravings with which his great work upon anatomy is illus- 

 trated. 



My work in five volumes was intended as a book of reference, which I 

 hope will continue to be useful to those who desire an account of the litera- 

 ture of physiology, as well as a statement of the facts of the science. I 

 have always endeavored, in public teaching, to avoid giving undue promi- 

 nence to points in which I might myself be particularly interested, from 

 having made them subjects of special study or of original research. In my 



