A STUDY 



OF SOME 



NORMAL AND ABNORMAL MOVEMENTS 



PHOTOGRAPHED BY MUYBRIDGE. 



BY 



FEANCIS X. DERCUM, M.D., Ph.D., 



INSTRUCTOR IN NERVOUS DISEASES, UNIVERSITY OF PENNSYLVANIA. 



In the foHowing study the writer has made no attempt to give 

 a systematic description of any of the plates, but only to present 

 the salient features of the more important clinical subjects investi- 

 gated. Naturally these subjects are of greater interest to neurol- 

 ogists than to others. The normal walk, however, possesses an 

 interest that is general, and the writer believes that the Muybridge 

 method has in this field, as in others, yielded new results. 



In addition to the serial photographs which have been pub- 

 lished, Mr. Muybridge kindly made, upon request, a number of 

 clinical photographs by means of a camera armed with a fenes- 

 trated wheel, — i.e., a Marey's wheel. Some of these pictures are 

 hero reproduced. 



Thanks are due to Drs. S. Weir Mitchell, William Pepper, H. 

 C. Wood, Charles K. Mills, and James H, Lloyd for the oppor- 

 tunity of photographing various patients under their care. 



The writer desires also to express his obligations to Mr. Muy- 

 bridge for his great and many courtesies, which necessitated not 

 only encroachment upon his most valuable time, but also the 

 occasional adoption of methods not included in his original enter- 

 prise. 



Regarding the various trajectories depicted in this monograph, 

 it is of course not claimed that they are absolutely accurate, but 

 merely as close an approximation to the truth as the method of 

 research permits. 



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