INTRODUCTION. 5 



Burgess, appeared in 1839, and to this work I shall fre- 

 quently refer in my thirteenth Chapter. 



In 1862 Dr. Duehenne published two editions, in 

 folio and octavo, of his ' Mecanisrne de la Physionomie 

 Humaine,' in which he analyses by means of electricity, 

 and illustrates by magnificent photographs, the move- 

 ments of the facial muscles. He has generously per- 

 mitted me to copy as many of his photographs as I de- 

 sired. His works have been spoken lightly of, or quite 

 passed over, by some of his countrymen. It is possible 

 that Dr. Duehenne may have exaggerated the impor- 

 tance of the contraction of single muscles in giving ex- 

 pression; for, owing to the intimate manner in winch 

 the muscles are connected, as may be seen in Henle's 

 anatomical drawings 7 — the best I believe ever published 

 — it is difficult to believe in their separate action. Never- 

 theless, it is manifest that Dr. Duehenne clearly appre- 

 hended this and other sources of error, and as it is known 

 that he was eminently successful in elucidating the 

 physiology of the muscles of the hand by the aid of elec- 

 tricity, it is probable that he is generally in the right 

 about the muscles of the face. In my opinion, Dr. 

 Duehenne has greatly advanced the subject by his treat- 

 ment of it. Xo one has more carefully studied the con- 

 traction of each separate muscle, and the consequent 

 furrows produced on the skin. He has also, and this is 

 a very important service, shown which muscles are least 

 under the separate control of the will. He enters very 

 little into theoretical considerations, and seldom at- 

 tempts to explain why certain muscles and not others 

 contract under the influence of certain emotions. 



A distinguished Trench anatomist, Pierre Gratiolet, 



7 ' Handbuch der Systematischen Anatomie des Men- 

 schen.' Band I. Dritte Abtheilung-, 1858. 



