SUPERIOR FACE OF THE BODY. 



133 



femoral movements extensive ; impulsion is transmitted horizontally, 

 but the general structure is not adapted to increase the fixation of the 

 spinal column. Velocity is increased at the expense of force. 



The first conformation, therefore, should exist in horses which are 

 employed to carry burdens or pull heavy loads ; the second is found 

 in those which are adapted to rapid locomotion with little or no 

 weight to carry, those whose value depends upon their qualities of 

 speed. 



2d. Variations in the Inclination of the Ischium. — When it is tlie ischium 

 which is lowered (Fig. 39), the croup, AB', 

 is more oblique, and ai^pears longer. 

 The length of the ischio-tibial muscles, 

 B^E, diminishes, but they have an inci- 

 dence of insertion more favorable, whether 

 for the rotation of the cox£e, in view of 

 fixing the spinal column, or the flexion of 

 the leg during progression. 



The coxo-femoral angle, AOD, does 

 not vary, and the extension of the femur 

 preserves its amplitude, provided the ilium, 

 AO, remain well directed. 



The force of propulsion, at the same 

 time, continues to be transmitted in its 

 proper direction, OA. 



Nevertheless, the distance, B^E, be- 

 tween the ischium and the tibia dimin- 

 ishes, which can only be compensated 

 by an increase in the femoro-tibial angle, 

 ODE, thus giving to the bones a more 

 vertical direction, such as is often seen 

 in thoroughbred horses, in which the tibia is ordinarily but little inclined. 



The gluteal muscles, A C, do not vary. 



What are the conclusions from these statements? Simplv this : 

 that the obliquity of the croup, due only to the lowering of the 

 ischium, or, if it be preferred, of the point of the buttock, favors 

 again force at the expense of speed, but in a manner less prejudicial 

 than in the preceding case, since the femoral amplitude, as well as a 

 good direction of the force of impulsion, are preserved. 



This conformation, if it be not exaggerated, will be excellent for 

 most ordinary services, because it corresponds more uniformlv to the 

 mean requirements of power, resistance, and velocity demanded from 

 the horse of to-day. 



3d. Simultaneous Variations of the Ischium and the Ilium. — If the 

 angle, A OB, instead of preserving its mean dimension, becomes smaller 



Fig. 39. 



