the withers of from two and a quarter to two and a half 

 inches. In order that the horse built in front for a 

 sprinter shall keep his equilibrium, it will be necessary 

 to lower his hind quarter and consequently to make his 

 femur and his tibia come closer to the horizontal. 



But this change of the slope of the femur gives the 

 ischio- femoral muscles an insertion very oblique and con- 

 sequently disadvantageous ; to correct it we must lower 

 the ischium, and to that end the hip must be made to 

 rotate downward on a horizontal axis perpendicular to 

 the median plane of the body. The ischio-femoral 

 muscles and ischio-tibials which are the most powerful 

 muscles of the organism and which play a preponderating 

 role in propulsion will, by this fact, be shortened, and 

 that is an advantage, from the point of view of speed. 



The greater the propulsion the more rapid will be the 

 rotation of the hind leg. Now it is evident that for a 

 given nervous impulse a short muscle will arrive more 

 quickly at its maximum contraction than a long muscle. 

 The propulsive force will then be applied more quickly 

 with a sloping croup and short ischio-tibials than with a 

 horizontal croup and long ischio-tibials. 



The sprinter then, whose theoretical model has just 

 been drawn for us, is not a theoretical animal ; he exists ; 

 one can even say he exists almost entirely alone at the 

 present time. Short distance races have been respon- 

 sible for making this conformation the common con- 

 formation of the race. 



At a standstill the model appears as follows : Shoulder 

 upright, arm very much inclined, elbow to the rear, 

 pasterns rather short than long ; steep croup, and sloping 

 femur, stifle to the front, rump short and rounded ; mus- 

 cles much in evidence. The general appearance is short 

 and the four feet are close together. 



