160 THE EXTERIOR OF THE HORSE. 



reader against certain ideas which are too absohite, and which exist 

 arnono- horsemen. Some prefer the cylindrical chest for slow and 

 heavy motors ; they reject it, on the contrary, for rapid services, in 

 which they would prefer the elliptical form. The latter form, whilst 

 giving equal space within the chest, tends to limit the lateral displace- 

 ments of the centre of gravity, and thus facilitates the velocity of the 

 gait. Others insist that there is sufficient compensation between the 

 two forms, but consider width of chest as a beauty, or point of merit, 

 in all cases. 



We have seen, when speaking of the ribs, that a high chest is 

 spacious only on account of its pro]>ortional width, but tlie relation 

 between the vertical and the transverse diameters varies less than is 

 generally thought. The development in one direction very often carries 

 with it a correlative development in the other. The digressions which 

 seem to contradict this principle are more apparent than real, for the 

 condition of the body has much influence upon the external dimensions 

 of the chest. Take a horse in good health, vigorous, well proportioned, 

 and subject him to excessive work and insufficient food, and measure 

 his chest when emaciation has reached its extreme limits. Not only is 

 he unrecognizal)le in his general form, but his narrow thorax and his 

 flat ribs have modified the correlation of his two thoracic diameters, and 

 we shall be astonished to find it to be 1.4, when, for example, it was 

 1.2. When the animal is ill cared for, when good nourishment and 

 moderate exercise no longer maintain the harmonies of the economy, all 

 the functions are diminished, especially those of respiration and circula- 

 tion. The chest tends to become contracted, at the same time that the 

 muscles become smaller, for the lungs are less active in the animal 

 which is emaciated. 



To make a contrary experiment, take the same horse and entirely 

 change his conditions of existence ; his chest will reassume its form, 

 according as its muscles augment in volume, density, and energy. 



The training which animals destined for the race-course undergo, 

 and that which results from the special labor to which work-horses are 

 subjected, constitute, again, important causes of a development of fulness 

 of the chest. In the horse, as in man, muscular gymnastics have the 

 effect of increasing the thoracic perimeter. If we were not convinced 

 of this fact in practice, our purchasing officers would every day refuse 

 horses whose chest is not perfect at the moment of the sale. Our 

 remounts take them because they know that this defect will partly dis- 

 appear after sufficient exercise. 



Thus, in our opinion, amplitude of all the thoracic diameters should 



