198 THE EXTERIOR OF THE HORSE. 



ground, is carried forward, and finally establishes a new point of 

 contact. Directed obliquely downward and backward at the beginning, 

 the member is directed in an inverse sense at the termination. It 

 therefore successively becomes shortened, elongated, and finally assumes 

 a new point of contact. 



1. The shortening manifests itself more particularly during the 

 motion from to 2 (Fig. 55). It is characterized at first by the maxi- 

 mum flexion of the pastern producing a closure of the angle of the 

 fetlock, of the canon, and of the forearm, resulting in a diminution 

 of the angle of the carpus and of the elbow. Arrived at the point 2, 

 the angle of the fetlock already begins to open in consequence of the 

 straightening of the pastern. As to the shoulder, it contributes, by its 

 backward rotation, in the shortening of the limb and in closing the 

 scapulo-humeral angle, though only to a small degree. 



The diminution of the length of the member is therefore progressive, 

 and passes from below upward by a greater and greater flexion of the 

 articular angles. 



2. The elongation, which commences at 2 (Fig. 55) by the exten- 

 sion of the fetlock, is continued to 3 by that of the metacarpus, by 

 the opening of the angle of the elbow, and, finally, by that of the 

 shoulder. These phenomena are not all simultaneous. They are due 

 to a gradual and successive extension of the pastern, the canon, and the 

 arm, and the lengthening of the inferior extremity of the member 

 commences before the shortening of its superior part has reached its 

 maximum. 



The preparation to touch the surface carries the anterior mem- 

 ber to its limit of extension. The radio-metacarpal angle is effaced ; 

 those of the elbow and the shoulder now attain their maximum sepa- 

 ration. As to the pastern, it extends obliquely downward and forw^ard ; 

 the foot is resting in the same axis. 



2. Action of the Posterior Member (Fig. 56). 



The posterior member, being an agent of attenuation, impulsion^ 

 and ambulation, offers attitudes analogous to those of the anterior. 



A. Phase of Contact. — Like its homologue, this member arrives 

 in station in a state of extension whose degree varies with the length 

 of the pace and the nature of the gait. During this phase it also 

 deadens the concussion against the ground and develops the force of 

 impulsion ; having accomplished these, it again prepares for a position 

 of station. 



1 . The attenuation of the concussion is effected from to 2 by 



