406 THE EXTERIOR OF THE HORSE. 



contractile organ by fractional portions, at equal intervals, and in very 

 close succession. But it is certain that the intensity of these portions 

 and the rapidity of their succession have an influence upon the value 

 of the effort to be produced. With regard to this, every one knows 

 the preponderance of the will over the energy of physical exercise. 

 We will see farther on, in speaking of endurance, that the individual 

 differences bearing u])<)n this influence are extremely variable. For 

 the present, we will confine ourselves to proving the necessitv of an 

 intense nerve stimulation in those motors which have to work en mode 

 de masse, or perform force labor. 



This being said, how shall we appreciate the two preceding data in 

 the examination of the external form ? This is easily answered : bv 

 the mass of the muscles, or, if preferred, by the approximative estima- 

 tion of the weight, which is generally proportional to the former ; 

 afterM'ards by the quantity of blood possessed by the animal examined. 

 When speaking of the mass of the nniscles, we mean the surface of 

 their transversal section, which is the more exteuded as the number of 

 elementarv fibres is itself g-reater. 



These are the two requisites which must first of all be found in the 

 motor en mode de inasse. 



There are still others, which are, however, only the necessary con- 

 sequence of the latter. Thus, we will seek more particularly an ample, 

 short, cylindrical body, close to the ground, and with strong loins ; 

 solid, thick, and wide members; a base of support a little wide, to 

 give more stability to the equilibrium ; developed extensors, for it is 

 by the extension of the locomotory columns, vigorously propped upon 

 the ground, that the animal moves his burden ; such are the cervical, 

 dorso-lumbar, scapular, pectoral, olecranon, antibrachial, gluteal, crural, 

 and tibial muscles. We must make sure of their compactness and 

 their density, the width and the thickness of the articulations ; the 

 approximative length and force of all the osseous prominences : the 

 trochiter, olecranon, trochanter, calcaneus, etc. ; the perpendicularity 

 of the muscular insertions, from a suitable inclination of the locomotory 

 segments ; the delicacy of the skin ; the expression and vivacity of the 

 physi(jgnoniy ; finally, the ease, the energy, and the power with which 

 the subject will accomplish his work, ivill bear his collar, as it is 

 expressed in ordinary language. 



