PREFACE TO FIRST EDITION 



The plan followed in the presentation of the subject of this 

 volume is rather different, so far as the author is aware, from that 

 set forth in any similar volume. This plan, however, he feels to 

 be a logical one and has followed it with satisfactory results during 

 a period of three years in his own classes at the University of Penn- 

 sylvania. The main point in which the plan of the author differs 

 from those previously proposed is in the treatment of the food stuffs 

 and their digestion. 



In Chapter IV the " Decomposition Products of Proteids " has 

 been treated although it is impracticable to include the study of this 

 topic in the ordinary course in practical physiological chemistry. 

 For the specimens of the decomposition products, the crystalline 

 forms of which are reproduced by original drawings or by micro- 

 photographs, the author is indebted to Dr. Thomas B. Osborne, of 

 New Haven, Conn. 



Because of the increasing importance attached to the examina- 

 tion of feces for purposes of diagnosis, the author has devoted a 

 chapter to this subject. He feels that a careful study of this topic 

 deserves to be included in the courses in practical physiological 

 chemistry, of medical schools in particular. The subject of solid 

 tissues (Chapters XIII, XIV and XV) has also been somewhat 

 more fully treated than has generally been customary in books of 

 this character. 



The author is deeply indebted to Professor Lafayette B. Mendel, 

 of Yale University, for his careful criticism of the manuscript and 

 to Professor John Marshall, of the University of Pennsylvania, for 

 his painstaking revision of the proof. He also wishes to express 

 his gratitude to Dr. David L. Edsall for his criticism of the clinical 

 portion of the volume ; to Dr. Otto Folin for suggestions regarding 

 several of his quantitative methods, and to Mr. John T. Thomson 

 for assistance in proof reading. 



For the micro-photographs of oxyhaemoglobin and haemin repro- 

 duced in Chapter XI the author is indebted to Professor E. T. 

 Reichert, of the University of Pennsylvania, who, in collaboration 

 with Professor A. P. Brown, of the University of Pennsylvania, is 

 making a very extended investigation into the crystalline forms of 



