30 PRINCIPLES OF VETERINARY SCIENCE 



is found as a connecting tissue framework id various parts of the 

 body. Tendons and ligaments are composed almost entirely 

 of it. It is not extensile. 



(6) Yellow elastic tissue, which is firmer than the white fibrous, 

 is much more extensile. It forms the ligamentum nuchse, that 

 broad and elastic support stretching from the head to the 

 withers. The walls of the blood-vessels and the air tubes of the 

 lungs also contain yellow elastic fibers. 



(c) Fatty, or adipose tissue, which serves as a storehouse for 

 excess fat, occurs where the fibrous connective tissue is arranged 

 loosely so that spaces are formed between the bundles of fibers. 

 Little droplets of oil, that finally coalesce to form a single globule, 

 collect in the cells and distend them so that the protoplasm and 

 nucleus appear to form a sort of cell capsule. Fat cells, therefore, 

 may be regarded as modified connective-tissue cells. Fatty tissue 

 is found interwoven or intermingled with the muscles and the 

 vital organs and under the skin where it forms an effective cover- 

 ing or insulator for the body to prevent rapid radiation of heat. 

 On this account, a fat animal needs less food than a lean one to 

 maintain itself. The amount of fatty tissue in the body varies 

 with the age and condition of the animal, but is more pronounced 

 in later life. Cold weather induces fat production, as is seen by 

 the fact that animals increase in weight during the winter. Fat 

 from the carcass of the ox. is known as beef tallow or suet; that 

 from the hog as lard; and that from the sheep as mutton tallow. 



2. Cartilaginous tissue is glass-like in appearance, translucent, 

 homogeneous, tough, and highly elastic, so is placed where these 

 qualities are needed. It cuts like cheese and is commonly named 

 "gristle." Cartilage cells are peculiar in character and relatively 

 few in number. All cartilage in the body is surrounded by a 

 membrane known as the perichondrium, a fibrous tissue which 

 carries blood-vessels to nourish the cartilage cells. 



There are two kinds of cartilaginous tissue: (a) Hyaline carti- 

 lage is a bluish- white color and covers the ends of long bones; (6) 

 fibrous cartilage is white and found between vertebrae. In the 

 embryo most bones are represented by cartilage; later this is 

 usually replaced by bone tissue. The rings of the trachea, the 

 epiglottis, and the covering at the ends of long bones are examples 

 of cartilaginous tissue which persists in the mature animal. 



3. Bony tissue, like other tissues, is composed of organic and 



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