ACTION OF CURBS. 79 



Any alteration in the position of a well broken and correctly 

 bitted horse's head, while he is being ridden, should be effected 

 by a corresponding alteration in the position of the rider's 

 hands, and not by a change of reins ; because such a change 

 could not always be made with precision and without danger, 

 as when crossing a difficult country, for instance. 



In practice, we find that the employment of a curb has a 

 tendency to make a horse gallop " round " : in other words, to 

 make him bend his knees too much ; because when his head 

 is brought down by the action of the curb, the direction of the 

 neck muscles, which draw the fore limbs forward, will not be 

 inclined sufficiently upwards to enable the feet to clear the 

 ground without undue bending of the knees. Although this 

 effect of the curb on the action of the horse may be dis- 

 regarded when perfect control, rather than speed, is demanded, 

 it has served to practically banish curbs from racing stables. 



If we examine the under surface of the lower jaw, we shall 

 find that the bone of the chin-groove (p. 77) is smooth and 

 rounded ; and that immediately above it, the edges of the 

 branches of the lower jaw are sharp and sensitive. Hence we 

 may accept the direction of Major Dwyer (Seats and Saddles] 

 that the curb-chain should lie in the chin-groove, without its 

 being given any tendency to mount upwards. 



As the bars are more sensitive than the tongue, the port 

 has been devised to take pressure off the latter and put it on 

 the former, in order to increase the severity of the bit. By 

 inclining the port forward (p. 83), the tongue will be still 

 more relieved of pressure. 



When a curb is used without a curb-chain (Fig. 93), the 

 fulcrum of the lever is supplied by the head-stall, and the 

 weight is the corners of the mouth, against which the mouth- 

 piece presses. Hence, the removal of the curb-chain some- 

 times acts well with a horse that carries his head too low. 



