The Veterinary Science 
PART I. 
ANATOMY OF THE HORSE. 
CHAPTER I. 
BONE. 
BONES are hard, yellowish-white, insensitive objects 
which form the skeleton of animals. Living bone is 
bluish pink, insensitive and elastic. Exposure to air 
causes it to become diseased and blackened, very sensi- 
cive and painful. 
Bones are made up of two kinds of matter — animal, 
which makes the bone tough and elastic, and earth};, which 
makes it hard and brittle. In young animals the animal 
matter forms one-half of the substance, which afterwards 
diminishes to one-third as the animal advances in age. This 
is why old animals' bones are easier to fracture and harder 
to mend. 
1. Covering of Bone. — Bones are covered by a tough, 
fibrous, inelastic membrane called periosteum, which can be 
seen by examining the bone of an animal which has just died. 
The only exception to this is at the joints where one bone 
articulates with another, and where a tendon or muscle plays 
over a bone ; here ^we find its place taken by articular carti- 
lage. 
2. Contents of Bone. — Red marrow is found in the ex- 
tremities or near the ends of bones, while white marrow is 
found in the shaft. 
3. Classes of Bone. — Bones are classed as long, flat and 
irregular. Long bones are found in the extremities or legs, 
and serve as levers for traveling and pillars to support the 
body. It is well to remember, that each long bone is divided 
into a shaft and two extremities. Flat bones are found where 
vital organs need protection. Example: Shoulder blade and 
ribs, to protect the heart and lungs ; pelvic or hip bones, to 
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