It may not be considered irrelevant if he repeats what he on that occasion said in his analysis of the quadrupedal walk:—
"So far as the camera has revealed, these successive foot fallings are invariable, and are probably common to all quadrupeds....
"It is also probable that these photographic investigations—which were executed with wet collodion plates, with exposures not exceeding in some instances the one five-thousandth part of a second—will dispel many popular illusions as to the gaits of a horse, and future and more exhaustive experiments, with the advantages of recent chemical discoveries, will completely unveil all the visible muscular action of men and animals even during their most rapid movements....
"The employment of automatic apparatus for the purpose of obtaining a regulated succession of photographic exposures is too recent for it to be generally used for scientific experiment or for its advantages to be properly appreciated. At some future time the philosopher will find it indispensable for many of his investigations."
The great interest manifested in the results of his preliminary labors convinced the Author that a comprehensive and systematic investigation with improved mechanical appliances, and newly-discovered chemical manipulations, would demonstrate many novel facts, not only interesting to the casual observer, but of indisputable value to the Artist and to the Scientist. This investigation and the subsequent publication in the elaborate manner determined upon, assumed such imposing proportions, and necessarily demanded so large an expenditure, that all publishers, not unnaturally, shrank from entering the unexplored field.
In this emergency, through the influence of its Provost, Dr. William Pepper, the University of Pennsylvania with an enlightened exercise of its functions as a contributor to human knowledge, instructed the Author to make, under its auspices, a comprehensive investigation of "Animal Locomotion" in the broadest significance of the words, (see appendix B) and some of the Trustees and friends of the University constituted themselves a committee for the purpose of promoting the execution of the work. These gentlemen were Dr. William Pepper, Chas. C. Harrison, J. B. Lippincott, Edw. H. Coates, Samuel Dickson and Thomas Hockley.
The Author acknowledges his obligations to these gentlemen for the interest they took in his labors; for without their generous assistance the work would probably never have been completed; the total amount expended—nearly forty thousand dollars—being entirely beyond his own resources. To Drs. F. X. Dercum, Geo. F. Barker and Horace Jayne, of the University, the Author is also indebted for much valuable assistance.
STUDIO, APPARATUS, AND METHOD OF WORKING.
For a proper appreciation of the care taken in the Investigation of Animal Locomotion at the University of Pennsylvania to ensure accurate record of the consecutive phases of the various movements, attention to the system adopted is necessary.