1088 



GENERAL ANATOMY OR HISTOLOGY. 



three purposes in the animal economy. In the form of ligaments it serves to 

 bind bones together ; in the form of tendons, it serves to connect muscles to bones 

 or other structures, and it forms an investing or protecting structure to various 

 organs in the form of membranes. Examples of where it serves this latter office 

 are to be found in the muscular fascise or sheaths, the periosteum, and perichon- 

 drium ; the investments of the various glands (such as the tunica albuginea testis, 

 the capsule of the kidney, etc.), the investing sheath of the nerves (epineurium), 

 and of various organs, as the penis and the eye (sheath of the corpora cavernosa 

 and corpus spongiosum, and of the sclerotic). In \vhite fibrous tissue, as its name 

 implies, the white fibres predominate, the matrix being apparent only as a cement- 

 substance, the yellow elastic fibres comparatively few, while the tissue-cells are 

 arranged in a special manner. It presents to the naked eye the appearance of 

 silvery-white glistening fibres, covered over with a quantity of loose, flocculent 

 tissue which binds the fibres together and carries the blood-vessels (Fig. 612). 

 It is not possessed of any elasticity, and only the very slightest extensibility ; 

 it is exceedingly strong, so that upon the application of any external vio- 



FIG. 612. -Connective tissue. (Klein and 

 Noble Smith.) a. The white fibrous element 

 a layer of more or less sharply-outlined, paral- 

 lel, wavy bundles of connective-tissue fibrils. 

 On the surface of this layer is b, a network of 

 fine elastic fibres. 



FIG. 613. Tendon of mouse's tail, stained 

 with hsematoxylin, showing chains of cells 

 between the tendon-bundles. (From Quain's 

 Anatomy. E. A. Schafer.) 



lence the bone with which it is connected will fracture before the fibrous tissue 

 will give way. In ligaments and tendons the bundles run parallel with each 

 other ; in membranes they intersect one another in diiferent places. The cells 

 occurring in white fibrous tissue are often called " tendon cells." They are 

 situated on the surface of groups of bundles and are quadrangular in shape, 

 arranged in rows in single file, each cell being separated from its neighbors by a 

 narrow line of cement-substance. The nucleus is generally situated at one end 

 of the cell, the nucleus of the adjoining cell being in close proximity to it (Fig. 

 613). Upon the addition of acetic acid to white fibrous tissue it swells up into a 

 glassy-looking, indistinguishable mass. When boiled in water it is converted 

 almost completely into gelatin. The white fibres being composed of the albu- 

 minoid collagen, which is often regarded as the anhydride of gelatin. 



Yellow Elastic Tissue. In certain parts of the body a tissue is found ^hich 

 when viewed in mass is of a yellowish color, and is possessed of great elasticity, so 

 that it is capable of considerable extension, and when the extending- force is with- 

 drawn returns at once to its original condition. This is yellow elastic tissue, 

 which may be regarded as a connective tissue in which the 'yellow elastic fibres 



