COMPOSITION OF BONES. Ill 



monstrous production, in organs which do not produce it 

 in a state of health, as the brain, the heart, and the pla- 

 centa *. 



The ordinary colour of bone is white. This, however, 

 is usually mixed with other colours in the teeth of herbivo- 

 rous quadrupeds. The bones of some varieties of the com- 

 mon fowl approach to blackness, and in some fishes they 

 are tinged with green. The nature of the food exercises a 

 considerable influence over the colour, as demonstrated by 

 the red tint which the bones of fowls acquire, when mad- 

 der is mixed with their food. 



The texture of bones exhibits many remarkable varie- 

 ties. It is compact in some places, as the teeth and bones 

 of the ear, fibrous as the bones of the head in a footus, 

 or cellular as those of the head of the cetacca. In bones, 

 there are likewise tortuous holes, termed sinuses, differing 

 from those containing the bloodvessels or marrow, and 

 communicating, more or less, directly with the exterior of 

 the body. 



The surface of particular bones is irregular, presenting 

 eminences which are termed processes, (apophyses.) When 

 these processes are united to the bone by the intervention 

 of cartilage, which, with age, becomes ossified, they arc 

 termed Epiphyscs. 



As intimately connected with bone, we may here take 

 notice of Cartilage. This can scarcely be said to differ \\\ 

 its nature, from the cartilaginous basis of the bone. It is 

 of a fine fibrous structure, smooth on the surface, and re- 

 markably elastic. It covers those parts of bones which are 

 exposed to friction, as the joints, and is thickest at the 

 point of greatest pressure. By its smoothness, it facili- 

 tates the motion of the joints, and its elasticity prevents the 

 bad effects of any violent concussion. It is intimately 



* MONRO'S Outlines of Anatomy., p. 63. 



