196 THE EXTERIOR OF THE HORSE. 



formulate these into intelligible propositions. As a whole, the conclu- 

 sions which have been deduced are exact ; but if we endeavor to make 

 a more minute analysis of these phenomena we shall find that they are 

 not so easily worked out. 



Strictly speaking, the limb of a horse cannot be compared to a long 

 lever which alternates by turns round its inferior extremity when the 

 latter is related to the surface of support, or its superior when it is 

 lifted. In other words, the displacements of the leg are not assimilable 

 to those of an oscillating pendulum, as Captain Raabe and his disciples 

 have supposed. 1 They result from a series of partial movements which 

 influence each other mutually and give to the articular centres very 

 complicated trajectories. The recognition of these secondary actions 

 offers interest from a point of view of the particular mechanical role 

 fulfilled by each region. It is necessary to make some remarks con- 

 cerning this statement. 



MM. Marey and Pages, 2 in their recent and valuable researches 

 with the aid of chrono-photography (see Generalities upon the Gaits), 

 have been enabled to register the successive positions of the different 

 bony segments of locomotion and the relative duration of their revo- 

 lution during the execution of the two principal phases of contact and 

 of elevation of a complete step. 



Let us see what interpretations can be given to the phenomena 

 indicated by these original investigations. Take, for example, the 

 movements of the members in the ordinary trot ; like MM. Marey and 

 Pages, we will choose, among the numerous positions aifected by these 

 apparatus, a certain number of attitudes well characterized by the 

 extension and flexion of some segments, or by important modifications 

 of the articular trajectories. 



i. Action of the Anterior Member (Fig. 55). 



A. Phase of Contact. The anterior member (which during 

 this phase arrives at a state of rest in an attitude of extension w r hose 

 degree varies with the extent of the pace and the nature of the gait) 

 should successively fulfil two very distinct roles, of which the purposes 

 are, first, to deaden the shock of concussion against the soil, and next, 

 to extend itself. After this process is over, it again prepares to elevate 

 itself. 



1 These views have been demonstrated in a recent work entitled L'art e"questre, par M. 

 Barroil, p. 21 et suiv., Paris, 1887. Chez Rothschild. 



1 Marey et Pagds, Analyse cinmatique des allures du cheval, in Comptes-Rendus de 1'Acade- 

 mie des sciences, 27 Septembre, 1886; ibid., Mouvement du membre pelvieu chez 1'homme, 

 1'elephant et le cheval, in Comptes-Rendus, 18 Juillet, 1887. 



