6 FROM THE PREFACE TO THE FIRST EDITION 



followed may not be out of place. It is obvious that many 

 of the exercises require more than one person for their per- 

 formance ; and it may be said that, except in the case of 

 the simpler experiments and the chemical work as a whole, 

 which each student does for himself, it has been found 

 convenient to divide the class into groups of four, each 

 group remaining together throughout the session. It is 

 possible that some may find a group of four too large a unit, 

 and it is certain that three, or perhaps even two, would be 

 better; but in a large school so minute a subdivision is 

 hardly possible, without entailing excessive labour on the 

 teachers. 



The systematic portion of the book is so arranged that it 

 can equally well be used independently of the practical 

 work, and aims at being in itself a complete exposition of 

 the subject, adapted to the requirements of the student of 

 medicine. 



I am indebted to my friend Dr. Arthur Clarkson for the 

 coloured drawings in Plate I., i, 3, and 4; Plate II.; 

 Plate III., i , Plate V., i and 2 ; and to my former pupil, 

 Dr. Kelly, for Plates III., 4, and IV., 4. 



As to the matter of the text, it is hardly necessary to say 

 that this book does not aspire to the dubious distinction 

 of originality ; and it is literally impossible to acknowledge 

 all the sources from which information has been derived. 

 In many cases names have been quoted, but names no less 

 worthy of mention have often been of necessity omitted. 



G. N. STEWART. 

 CAMBRIDGE, September, 1895. 



