CHEST-FOUNDER. 231 



will have the saddle eased and padded as soon as it begins to be of the least 

 inconvenience to the horse. 



MUSCLES OF THE BREAST. 



There are some important muscles attached to the breast connected with that 

 expansion of the chest which every horse should possess. In the cut, page 212, 

 are seen a very important pair of muscles, the perforates transversi, or pectoral 

 muscles, forming two prominences in the front of the chest, and extending back- 

 ward between the legs. They come from the fore and upper part of the breast- 

 bone ; pass across the inward part of the arm, and reach from the elbow almost 

 down to the knee. They confine the arm to the side in the rapid motion of 

 the horse, and prevent him from being, what horsemen would call, and what 

 is seen in a horse pushed beyond his natural power, "all abroad." Other 

 muscles, pectorales magni et parvi, the great and little pectorals, rather above 

 but behind these, go from the breast-bone to the arm, in order to draw back 

 the point of the shoulder, and bring it upright. Another and smaller muscle 

 goes from the breast-bone to the shoulder, to assist in the same office. A horse, 

 therefore, thin and narrow in the breast, must be deficient in important 

 muscular power. 



Between the legs and along the breast -Lone is the proper place in which to 

 insert rowels, in cases of inflamed lungs. 



CHEST-FOUNDER. 



These muscles are occasionally the seat of a singular and somewhat mysterious 

 disease. The old farriers used to call it anticor and chest-founder. The horse 

 has considerable stiffness in moving, evidently not referable to the feet. There 

 is tenderness about the muscles of the breast, and, occasionally, swelling. We 

 believe it to be nothing more than rheumatism, produced by suffering the horse 

 to remain too long tied up, and exposed to the cold, or riding him against a 

 very bleak wind. Sometimes a considerable degree of fever accompanies this ; 

 but bleeding, physic, a rowel in the chest, warm embrocations over the parts 

 affected, warm stabling, and warm clothing, with occasional doses of antimonial 

 powder, will soon subdue the complaint. 



CHAPTER XI. 

 THE CONTENTS OF THE CHEST. 



THE THYMUS GLAND. 



AT tl.c entrance of the trachea into the thorax, and ere it has scarcely pene- 

 trated between the first ribs in the young subject, it comes in contact with an 

 irregular glandular body, situated in the doubling of the anterior mediastinum. 

 1 1 is " the thymus gland," or, in vulgar language, the sweet-bread. In the 

 early period of utero-gestation, it is of very inconsiderable bulk, find confined 

 mostly to the chest; but, during the latter months, it strangely developes 

 itsdf, the superior cornua protrude out of the thorax and climb up the neck, 

 between the carotids and the trachea. They are evidently connected with the 

 thymus gland, and become parts and portions of the parotid glands. 



We are indebted to Sir Astley Cooper for the best account of the anatomical 



