

PREFACE TO THE SECOND EDITION. 



IN the preparation of the second edition of this book the author 

 has made no fundamental change in its arrangement or scope. 

 Additions and changes havp been made freely throughout the 

 work, with the object of keeping the presentation of the subject 

 abreast of the times, but as far as possible the additions have been 

 counterbalanced by the elimination of such material as could be 

 spared. The book remains, therefore, of practically the same 

 size, an object which the author has purposely kept in view, since 

 he is convinced that in text-books there is a natural tendency to 

 overexpansion which should be guarded against with care. New 

 figures have been introduced whenever it seemed that an actual 

 improvement could be effected by this means. 



The author has been gratified with the generous approval 

 accorded to the first edition and hopes that the present edition 

 may continue to find favor with teachers of physiology and medical 

 students, as well as among physicians who may feel the need of 

 keeping themselves in touch with the progress of physiology. There 

 are, in fact, many indications that the physiological side of medi- 

 cine is likely to receive a fuller recognition than has been given 

 to it in the recent past. Medical schools are providing courses in 

 experimental pathology and surgery, subjects in which physiological 

 methods and training are all important, and in clinical medicine 

 also it is becoming evident that the methods of physiological 

 experimentation and the application of physiological discoveries 

 are of practical value in diagnosis as well as in investigation. No 

 one doubts that anatomy, physiology, and pathology, using these 

 terms in a broad sense, constitute the basis upon which a rational 

 system of medicine must be constructed, but it would seem that, 

 in this country at least, the clinicians have failed to make full use 

 of the material offered to them by the subject of physiology. 

 Some explanation of this neglect is found in the fact -that the 

 physiologists themselves, not being practitioners, have no good 



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