CURBS.
A curb is a bit which acts as a lever, by means of the curb-chain that passes under the animal’s lower jaw ([Fig. 38]). [Fig. 39] shows a properly constructed curb for a horse with an ordinary sized mouth. The best curb which is in general use is the Ward Union ([Fig. 40]). The curb-chain should have broad and thick links, so that it may not hurt the lower jaw. This precaution can be supplemented by a leather guard or by passing the curb-chain through a rubber tube ([Fig. 41]). A chin-strap (Figs. [42] and [43]) is necessary to keep the curb in its place ([Fig. 44]).