PEEFACE TO THE SEVENTH EDITION. 



ten years have elapsed since the first appearance of 

 my text-book. Meanwhile, clinical medicine owes a rich acces- 

 sion of knowledge to investigations made, not only in her own 

 province, but in the provinces of physiology, pathological anat- 

 omy, and physiological and pathological chemistry. Important 

 questions have been settled ; obscure points rendered clear ; false 

 theories corrected, and errors recognized. 



Although, in preparing previous editions, I have taken pains 

 to keep my book well up to the existing state of science, to ren- 

 der account of the most important advances made in the study 

 of medicine and its kindred branches, yet the briefness of the 

 time allowed for this purpose owing to the rapidity with which 

 editions have been renewed rand the conviction that the true 

 value of many discoveries of supposed importance could be as- 

 certained only by a longer probation, have hitherto deterred me 

 from a full and thorough revision of the entire work. At last, 

 ten years after its first appearance, the proper moment seems to 

 have arrived. The somewhat longer respite now allowed me foi 

 my task, is due to the foresight of my publisher, who has made 

 the previous edition of triple the usual size. 



In the present (seventh edition), but few portions of the work 

 remain unaltered ; and even those few have nearly all undergone 

 revision on previous occasions. Most parts of it have received 

 valuable emendations, and have been enriched by copious addi- 

 tions. I have everywhere paid particular attention to the im- 



