146 THE EXTERIOR OF THE HORSE. 



There are, therefore, two elements to be considered in the width of 

 the pectoral region : whether it depend solely upon the volume of the 

 pectoral muscles, or if to this cause is also added a well-developed 

 thoracic cavity. In the former case, the width of the breast will vary 

 according to the general condition and health of the animal ; in the 

 latter, its variations, whatever they may be, cannot be presumed to be 

 due to narrowness or feeble development of the thorax. 



The width should not exceed certain limits ; for when these limits 

 are passed width of the breast becomes a defect, since it gives too large 

 an area to the base of support. Horses endowed with speed should be 

 well open in front, but their openness must not be excessive, because 

 the lateral displacements of the centre of gravity can only take place at 

 the expense of the velocity of the gait. 



The English thoroughbred is not too open in front, whilst his 

 chest, which appears narrow, is high and salient in such a way that the 

 extremity of the sternum is prominent and gives attachment to long 

 muscles. 



Draught-horses can, without being defective, be very open in front. 

 The lateral oscillations of the centre of gravity, being only prejudicial 

 to velocity, do not diminish the energy of his efforts. His power 

 depends upon his mass, and he demands, therefore, firm and volumi- 

 nous muscles. From this point of view we may regard a wide breast 

 as an absolute beauty, or as a point of great merit, because it gives 

 to the trunk the volume which is necessary for it to have in order to 

 overcome easily, but slowly, heavy resistances. 



When the breast is very narrow, it is said that the horse is closed 

 in front. In all such cases, this conformation, the opposite of the pre- 

 ceding, is defective. It indicates a feeble development of the muscular 

 system, and very often respiratory organs of small amplitude. If such 

 animals offer some appearance of energy when they are exercised, they 

 are generally incapable of enduring continuous and laborious work. 



Narrowness of the breast, as well as its width, may be congenital 

 or acquired. When it is congenital, it is observed in those subjects 

 which, at birth, show themselves to be defective in the development of 

 the muscular and the respiratory systems. When it is acquired, on the 

 contrary, it is consequent upon a state of emaciation, exhaustion, diverse 

 chronic diseases, and, in general, a profound debility of the organism. 

 In this case, the extremity of the sternum becomes salient, the points 

 of the shoulders project forward, and leave between them and the sterno- 

 humeralis muscles two deep depressions which terminate inferiorly the 

 jugular gutters. 



