56 MECHANISM OF EQUINE LOCOMOTION 



motion in the fore hand ) for the special prominence of the head and neck 

 will more or less rivet the attention of the eyes. Besides this, the centre of 

 gravity of the horse's body is nearer his fore legs than his hind ones. 



I may mention that as soon as fast antelopes, like the Indian Black Buck 

 and South African Spnngbok, get tired in their bounding kind of gallop, they 

 "settle down" to one resembling that of the horse (Figs. 133 to 148), 

 When the cheetah — ^who, as far as I can make out, gallops like the cat 

 (Figs. 166 to J 71), in a succession of leaps — becomes tired of that pace, 

 he drops into a walk or trot. 



On pages ^i ^^^ 54 ^ ^^"^e alluded to the effects of the lateral displacement 

 of the centie of gravity in causing fatigue. 



The pace which is the speediest, is also the most fatiguing ; for, as in fast 

 paces the centre of gravity will be carried further beyond its base of support 

 than at slow ones, a greater muscular effort will be required in them to form 

 a new base of support. We may see this if we compare, one with another, 

 Figs. 58, 61, 77, 1X2, and 144. 



Action of the Head and Neck in Locomotion. — During move- 

 ment, the head and neck act as a balancing pole in changing the position 

 of the centie of gravity from one side to the other, and in raising or 

 depressing it. Certain muscles of the neck draw the fore limb forward 

 and upward ; other muscles of the neck straighten out the head and neck, 

 and a third group bend them. 



Mechanism of the Fetlock Joint. — As Lecoq explains, " the weight 

 of the body, transmitted by the cannon-bone upon the upper articulating 

 surface of the long pastern bone, is the resistance to be overcome. The 

 fulcrum is the ground at the toe of the foot, and the power acts upon the 



Fig. 38.— Mechanism of Fetlock: Joini. 



sesamoid bones, which are at the back of the pastern ; the shortening of the 

 flexor muscles being the cause of the straightening of the angle formed by 

 their tendons." The diagram given in Figa 38 will show how this lever (one 

 of the second order) acts. In it we see that the distance between the power 

 and weight remains constant ; but their respective distances from the fulcrum 



