6 PREFACE. 



pathological conditions, bears the same relation to disorgan- 

 izing diseases of the liver that urea does to corresponding 

 conditions of the kidneys. The experiments by which these 

 facts have been developed are so repulsive and difficult that 

 there is little likelihood of their being extensively verified ; 

 and while the author confidently awaits the time when the 

 results of his investigations will be generally admitted, he is 

 satisfied at present with the acknowledgment that they are 

 entirely original. 



Within a short time, several mooted points of great 

 importance with regard to the physiological anatomy of the 

 liver and the kidneys have been definitively settled. It is 

 hoped that the chapters in which these anatomical questions 

 have been considered will be found to represent the latest 

 and most reliable views ; and it does not seem now that the 

 conclusions will be materially altered by future researches. 



The author feels that he has no apology to make for the 

 apparent delay in the issue of the present volume. His 

 labor upon it has been almost unremitting since the issue of 

 the volume on alimentation, digestion, and absorption; 

 and his chief endeavor has been to make it represent faith- 

 fully the existing state of the science, without sparing time 

 or pains. All he can promise is, that the remainder of the 

 work will be prepared with equal care, and, it is hoped, 

 within a shorter interval. 



NEW YORK, September, 1869. 



