PROGRESSION. 129 



making a total of 18. When he stood up in his stirrups, the 

 fore-hand received an addition of 12 kil. 



These gentlemen with justice observe, in concluding this ac- 

 count of their interesting experiments, that " although the differ- 

 ences caused by the position of the head and neck of the animal, 

 and of his rider, may not, under ordinary circumstances, be of any 

 great deal of consequence, yet do they acquire vast importance 

 in the course of work, such as racing or hunting, the preponderance 

 increasing enormously along with the fatigue." 



From these experiments we learn, that although the fore-hand 

 at all times has more weight to sustain than the hind, yet, in con- 

 sequence of the hind supporting more than its half of the trunk, 

 does this additional burthen not amount to what the head and neck 

 abstractedly would weigh; and we learn farther the important 

 fact, that a weight upon the fore-legs, which, in the ordinary or 

 natural position of the head and neck, amounts to 210 kilogrammes, 

 becomes, by reining-up, reduced to 200, and that, with the rider 

 on the back, a weight forward of 254 kilogrammes can be 

 diminished, by bringing the head with the bridle-hand into the 

 proper {managed) position, to 233, making a difference of 21 

 kilogrammes, or nearly 58 lbs. troy. These are results which 

 we, as veterinarians, shall be able to turn to useful account : to the 

 equestrian and riding-master they are full of the greatest interest. 



The limbs in the natural standing posture, placed as they are 

 in parallels with the line through the centre of gravity, and being 

 in themselves respectively so many co-operating centres of gra- 

 vity, and bearing each of them its due proportion of the weight 

 of the body, can none of them be moved in any material de- 

 gree out of the lines of gravity — which we may suppose to run 

 through their respective centres -without imposing additional 

 weight upon their fellows, on account of placing themselves in a 

 position disadvantageous for supporting the superincumbent load, 

 and consequently creating some feeling of uneasiness, in time 

 increasing to pain. The first act in progression is the result of 

 the stimulus of the will : the brain gives the order through the 

 nerves for the body to be moved forward ; one leg moves, the 

 other, through impulse, follows : the uneasiness created in the 

 frame by the elevation and projecture of one limb generating that 



s 



