COMPARATIVE LOCOMOTION OF DIFFERENT ANIMALS.* 



By E. J. Marey, 



Memhir of Instiinte of France. 



In the study of organized beings, it is a matter of special interest to 

 seek for tbe tie which exists between the special structure of each spe- 

 cies and its characteristic functions. Tiie more and more intimate 

 union of anatomy and comparative physiology will, without doubt, lead 

 to the discovery of the fundamental laws of morphogeny, laws which 

 will permit us from the form of an organ, to foresee its peculiar uses. 

 These relations are already partially within our grasp, so far as the 

 locomotor apparatus of vertebrates is concerned. The volume and length 

 of muscles, the relative dimensions of the bony rays of the limbs, the 

 form and extent of the articular surfaces, permit us to predict the gait 

 of a mammal. And, on the other hand, the correctness of these predic- 

 tions may be tested by means of chrono-photography, which fixes the 

 character of these movements in a series of instantaneous images. 



The readers of this journal already know how the gait of man, of 

 the horse, and of the principal mammals may be represented by true 

 geometrical diagrams on which one can readily trace the angular 

 motions of the different segments of the limbs, and the speed of each 

 part of the body, at every instant and for each gait. 



The different types of flight among birds and insects have also been 

 studied by means of chrono-photography. This method can be extended 

 to the analysis of the locomotion of all living beings, even to those mov- 

 ing in the field of the microscope. This done, it will then be possible 

 to unite and classify in a inctorial atlas a series of types of animal loco- 

 motion. These types, compared with the anatomical descriptions of 

 the various species will furnish the necessary elements for the compar- 

 ison which we wish to make. 



It will be a work of time to gather and compare all these anatomical 

 and j)hysiological data. The principal difficulty in the way of studying 



Translated from La Xafiire, September 2, 1893; vol. xxi, pp. 215-218. 



501 



