Vl PREFACE TO THE FIRST EDITION 



the most important facts of all, leaving matters of detail and controverted 

 questions to the text-books of physiological chemistry. In preparing these 

 sections of the book I have received very valuable advice from my distin- 

 guished friend Herr Professor Dr. K. A. H. Morner. 



I may say further that the discussion of the chemical processes of the 

 body is based in the main upon the text-books of Hammarsten and Neumeister. 

 The experienced reader will find also that I have made frequent use of the 

 physiological monographs which have appeared within recent years. Espe- 

 cially to be mentioned are the " Allgemeine Physiologic " of Verworn and 

 " Die Zelle und die Gewebe " of 0. Hertwig, which constitute the chief 

 sources of the chapter on the cell. 



With regard to the physiology of the sense organs I may state that I 

 have treated them in this book chiefly from the point of view of the prac- 

 ticing physician. For this reason the physical conditions of sensation have 

 been discussed rather fully, while those investigations on sense perception 

 falling within the borderland common to physiology and psychology, and of 

 themselves so extremely important, have been discussed only in roughest 

 outline, an exhaustive discussion being quite beyond the scope of the book. 



In the citation of authorities I have tried to hold a middle course between 

 the very numerous references found in many text-books and the entire ab- 

 sence of them found in others. I must acknowledge, however, that I have 

 not in all cases succeeded in finding the proper middle course. 



The few references given will direct the reader's attention to only the 

 more recent monographic discussions of the appropriate sections. Probably 

 I should have referred throughout to the " Handbuch der Physiologic " edited 

 by Hermann. I must content myself, however, with citing it here once for all. 



Among the many beautiful illustrations, which I owe to the liberality 

 of my publisher, the majority have been taken from the original papers of 

 the authors cited in the figures. Figs. 3, 6, 7, 55, 61, 80, 83, 86, 87, 88, 121 

 have been borrowed, with the courtesy of the publishers, from " Physiolo- 

 gischen Graphik " of Langendorff . 



EGBERT TIGERSTEDT. 

 STOCKHOLM, May 1, 1897. 



