PREFACE TO THE SECOND EDITION 



The generally favorable criticisms with which the first edition of the text- 

 book has been received and the necessity for a second edition in two years is 

 gratifying. If its reception may serve as a criterion of its usefulness as a book 

 intended primarily for the student of medicine, it is fulfilling the main pur- 

 pose of its authors. 



In the present edition some errors have been corrected and some para- 

 graphs have been rewritten, owing to the fact that important advances have 

 been made in the science even in the brief time elapsing between the two 

 editions. There has been however no change in the general plan and scope 

 of the work, as outlined in the preface to the first edition. 



THE AUTHORS. 

 AUGUST 15, 1911. 



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