MATERIALS FOR A MEMOIR 



OX 



ANIMAL LOCOMOTION. 



BY 



HAERISON ALLEN, M.D., 



EirERITUS PROFESSOR OF PHYSIOLOGY IN THE UNIVERSITY OF PENNSYLVANIA. 



INTRODUCTION. 



The writer has undertaken, at the request of the representa- 

 tives of the University of Pennsylvania, a series of studies on 

 animal locomotion. The subject has been approached from the 

 point of view presented by instantaneous photography, and has 

 been especially based ou the results obtained by Mr. Eadweard 

 Muybridge. He will also state that he is indebted to Professor 

 Thomas Eakius for facilities afforded in studying the results of an 

 experiment in the use of a modified form of Marey's wheel de- 

 vised by him, in photographing the action of the horse in motion. 



Many of the statements could have been deduced from data 

 already accessible to the writer, but since he wrote the paper 

 immediately after the inspection of the photographs his conclu- 

 siqns may be said to be based upon them. At the same time he 

 has not hesitated to include materials not embraced by the photo- 

 graphs. Whenever practicable the study of a given series was 

 carried on at the same time that the animal itself lay dissected 

 before him. For example, when studying the photographs of the 

 elephant, he had the good fortune, through the courtesy of Pro- 

 fessor Huidekoper, to dissect the limbs of an elephant. He has 

 also dissected the horse, the ox, the raccoon, the sloth, the skunk, 

 the Virginian deer, and the domestic cat. In the course of the 



