114 THE EXTERIOR OF THE HORSE. 



year, the period when the bones have attained their full length and the 

 body its complete development. In the mare it is less prominent than 

 in the gelding or the stallion. In the latter, however, in which the 

 anterior portion of the body is more extensively developed, it appears 

 usually tkiek, muscular, loiv, and effaced. 



The relative influence of all these causes it is easy to comprehend. 

 One may operate alone or several may be combined, and the height of 

 this region should not be attributed exclusively to one alone, as the sole 

 length of the spinous processes, for example, which hippotomists until the 

 present time have asserted without offering any proof to substantiate the 

 claim. Taking cognizance of this relation, we have endeavored to prove, 

 by numerous researches upon the living animal and the cadaver, that 

 this opinion is well founded. It is true that we have frequently found 

 an excess of the length of the spinous process of the fifth dorsal ver- 

 tebra (the culminating point of the region) in horses with high withers, 

 but we have also, all things being equal otherwise, none the less often 

 seen this process only equal to and even shorter than the others. 

 Moreover, we can affirm that this excess of length is not uncommonly 

 met with in horses in which the region appears depressed. 



The spinous processes are, therefore, subject to great variations in 

 animals not dissimilar in appearance These variations may attain five 

 centimetres in the one case or the other. 



It becomes evident, then, that other influences must assist in the 

 determination of the prominence of the withers. They are those 

 which we have enumerated above. Among them the most important, 

 doubtless, is that which refers to the mode of suspension of the thorax 

 between the anterior members. As to this assertion, our researches 

 leave not the least doubt. We daily meet horses which have the 

 same length of the ribs, the shoulder, and the spinous processes, the 

 same inclination of these processes and the scapula, and the same state 

 of muscular development, in which, nevertheless, the summit of the 

 withers does not, to the same degree, project beyond the top of the 

 shoulder. How can we explain this fact, unless it be due to differ- 

 ences in the degree of the elevation of the trunk in its attachment 

 to the anterior extremities? As a proof of this enunciation it has 

 been ascertained, in similar instances, that the distance from the 

 inferior surface of the thorax to the ground augments in direct ratio 

 with the projection of the spinous processes above the scapular carti- 

 lages. 



Let us remark, in passing, that in practice it is almost impossible 

 to establish the relative role which is exercised by the one or the other 



