PREFACE TO SECOND EDITION 



The opportunity has been taken in this second edition to eliminate 

 typographical errors and to alter the wording in certain chapters where 

 there was ambiguity of statement in the first edition. The most en- 

 couraging reception afforded the volume has fully confirmed the author's 

 conviction that modern acquaintance with physiology is fundamental 

 to sound medical and surgical practice. 



J. J. R. MACLEOD. 



Toronto, Canada. 

 1919. 



PREFACE TO FIRST EDITION 



The necessity of allotting the various subjects of the medical curric- 

 ulum to different periods, so that .the more strictly scientific subjects 

 are completed in the earlier years, has the great disadvantage that the 

 student, being no longer in touch with laboratory work, fails to employ 

 the scientific knowledge with full advantage in the solution of his clin- 

 ical problems. He is apt to regard the first two or three years in the 

 laboratory departments as inconsequential in comparison with the sup- 

 posedly more practical instruction offered during the subsequent clinical 

 years. He is taught by his laboratory instructors to observe accurately, 

 and to correlate the observed facts, so that he may be enabled to draw 

 conclusions as to the manner of working of the various functions of the 

 animal body in health, and before proceeding to his clinical studies, he 

 is required to show a proficiency in scientific knowledge, because it is 

 recognized that this must serve as the basis upon which his knowledge 

 of disease is to be built. When the clinic is reached, however, the meth- 

 ods of the scientist are not infrequently cast aside and an understanding 

 of disease is sought for largely by the empirical method ; namely, by the 

 endeavor to see and examine innumerable patients, to diagnose the case 

 according to the grouping of the signs and symptoms, and to treat it by 

 the prescribed methods of experience. So much has to be learned and so 

 much has to be seen during the clinical years, that the student gives little 

 thought to the nature of the functional disturbance which is responsible 

 for the symptoms; he fails to realize that after all, there is no essen- 



