vi PREFACE TO THE SECOND EDITION. 



The original purpose of this book has been main- 

 tained, and it is hoped that the second edition, contain- 

 ing double the letterpress and treble the number of 

 illustrations found in its predecessor, will in some cor- 

 responding measure improve upon the service which 

 the work has apparently rendered to students and 

 physicians. 



A. C. A. 

 PHILADELPHIA, July, 1894. 



