222 THE EXTERIOR OF THE HORSE. 



this region, we meet a horny excrescence to which has been given the name chest- 

 nut. It is small in animals of fine breeding. 



The anterior and posterior faces, convex from side to side, are covered by 

 muscles ; their thickness is proportional to the volume of the latter. 



Movements. The forearm, from the mode of union of its two 

 bones with themselves and with the humerus, can execute only two 

 principal movements : extension and flexion. 



The first, whose extent is directly proportional to the length of the 

 bones concerned and the degree of openness of the humero-radial 

 angle, carries the knee forward and upward, and enables the anatomical 

 foot to be moved in advance. This is accomplished just before the 

 foot touches the ground. 



The second takes place principally during the latter half of the 

 phase of contact, as is shown by instantaneous photographs. It con- 

 tributes, therefore, in a certain measure to the impulsive forces, since in 

 this period the member, as a whole, is directed obliquely downward 

 and backward. 



Beauties. In order to be in the most favorable conditions for 

 the production of velocity, the forearm should be long, wide, thick, and 

 well directed. 



Length. The length of the antibrachial lever should be con- 

 sidered from two different points of view : the one considers the absolute 

 length ; the other, its length as compared with that of the canon. 



a. Absolute Length. The absolute length of the forearm 

 should be as great as possible, for the reason that the arc which this 

 segment describes by its extremity is proportional to its length ; also, 

 because this length implies a corresponding length of the muscles 

 which cover it. It is upon these two factors that the velocity, in so 

 far as it is produced by the structures of this region, principally 

 depends. 



If the forearm be short, its oscillation, it is true, will be more 

 rapid, but the distance passed at each step will be less. It can only 

 preserve the velocity by a greater frequency of the movements, at the 

 expense of a loss of time and more fatigue. Again, the knee being 

 more elevated, the whole limb will be raised rather than projected for- 

 ward ; the animal will trot upon place, but with a short forearm the 

 movements will be more brilliant, easy, and harmonious, and the horse 

 is said to have high knee-action. In the cavalry horse, or in those 

 used in riding-schools and parades, this is, without doubt, a matter of 

 beauty, but perfection in this respect makes the horse more manageable, 

 and is therefore a useful qualification. A horse with a high knee- 



