CARRIAGE OF THE HEAD AND NECK. gi 



creased, they should be drawn back. Thus, any alteration 

 by the rider, of tension on the reins which might impede 

 the legitimate movements of the neck, is avoided. As 

 the joint which the head makes with the atlas (first vertebra 

 of the neck) is situated some distance below the top of 

 the head, it follows that if the muzzle be unduly stretched 

 out, the occipital crest (top of the head) will be brought 

 back, and the tension of the ligament of the neck lessened, 

 with consequent decrease of power in the muscles which 

 are attached to this ligament. The muscle which is at- 

 tached to the humerus and top of the head, also would 

 work to disadvantage, if the muzzle were stretched out 

 to a greater e.^tent than would bring the line of the face 

 at a right angle with the direction of this muscle, which 

 forms the upper border of the jugular groove. 



(3) To regulate the position of the Centre of Gravity. — 

 The more the head is advanced to the front, the more 

 unstable will be the equilibrium, and the greater will be 

 the speed during progression (p. 6g). Hence, the race- 

 horse, when galloping at full speed, will bring his head 

 forward as much as the other conditions which affect its 

 carriage will allow him to do. The cart-horse, if he has 

 good foot-hold and no bearing-rein, will also, when pulling 

 a heavy load, lower his head and stretch it out, so as to 

 bring the centre of gravity forward as much as possible. 

 Here I assume that the gromid is soft enough to allow 

 him to " dig his toes " into it, or, if it be rough, that he 

 is provided with toe-pieces on his front shoes. If, on the 

 contrary, the roadway is slippery, like the London streets 

 which are covered with asphalte or wood, the cart-horse 

 in heavy draught, being afraid of falling down if he throws 

 his weight into the collar, will try to keep the centre of 

 gravity back by holding his head high, while trusting 

 almost entirely to his hind legs to push the body forward. 

 When a horse rears, halts suddenly, or reins-back in heavy 

 draught (p. 130), he will raise his head and neck, so as to 

 bring the centre of gravity back. Any one who has 



