8 PREFACE. 



developments in physiology have been the result of experi- 

 ments upon living animals, by vivisections or otherwise, or 

 accurate experimental observations upon the human subject. 

 The great extension of this method of study is the cause of 

 the rapid advances the science is making at the present day. 

 For some years the author has been in the habit of employ- 

 ing vivisections in public teaching, and in this way has fre- 

 quently verified the observations of the earlier as well as the 

 more modern physiologists. A frequent repetition of experi- 

 ments has often enabled him to reconcile the discordant results 

 of the observations of others ; and following out new questions 

 which have presented themselves in the constant observa- 

 tion of the living organs, he has advanced some original 

 views regarding certain of the functions. A new method is 

 likewise presented for the analysis of the blood with reference 

 to its organic constituents. 



The plan of publication of the present work is one which 

 is novel in this country, but which has been adopted abroad, 

 particularly in France, in almost all elaborate treatises on phys- 

 iology. It is to be issued in separate parts, each, however, 

 forming a distinct treatise devoted to natural subdivisions of 

 the subject. The volume now issued embraces an Introduc- 

 tion, the Blood, Circulation, and Respiration. The remain- 

 ing volumes, three in number, will be issued yearly until the 

 work is finished, and will likewise be severally complete in 

 themselves. Simple and well-known anatomical and physi- 

 ological points have not been illustrated by engravings, 

 which have only been introduced where they seemed neces- 

 sary to elucidate the text. 



NEW YORK, October, 1865. 



