ANATOMY, UNSOUNDNESS, ^ND AGE OF A HORSE 37 



attached to bones by tendons. In such cases, the tendons, 

 at one extremity, are united to the end of the muscles, and 

 at the other to the bones. It is difficult to tell how the 

 muscle and tendon are joined, or by what means the union 

 is brought about, for the parts become insensibly blended. 



Ligaments. — These are fibrous structures arranged in 

 flat bands or bundles and sometimes in membranous 

 form. They are composed of white fibrous or yellow 

 elastic tissue, the former has a bluish-white, silvery ap- 

 pearance, the latter a yellow color and is very elastic. 

 Ligaments bind the ends of bones together and thus form 

 strong bonds of union at the joints. 



Connective tissue. — This consists of strong, fibrous lay- 

 ers and bands which furnishes a supporting network for 

 the muscles, skin and other tissues. Connective tissue 

 has only the passive action of support, and the more of it 

 a muscle contains the coarser and less powerful it will be ; 

 though it will be better able to resist the effects of ex- 

 ternal violence than one of finer grain. The connective 

 tissue, also, forms ligaments, tendons, surrounds bones, 

 cartilages, nerves and the like. Where the tissue is 

 present in large amounts the underlying parts will be ill- 

 defined. This is especially noticeable about the tendons 

 and ligaments below the knees and hocks, owing to the 

 absence of muscle about these parts. 



The thickness of the skin is a measure of the amount 

 of connective tissue contained in the muscle, and as the 

 action of this tissue is only passive, the more of it a 

 muscle contains, the slower will be the movements. 

 Hence the horse having a thick skin and ill-defined ten- 

 dons would warrant us in supposing that he was deficient 

 in quality. 



Circulatory system. — This consists of the heart, ar- 

 teries, capillaries and veins. The heart is the central 

 organ of the system and is divided into four chambers — 

 the right and left auricle and the right and left ventricle. 

 The action and the function of the blood will be best 



