68 LOCOMOTION. [CHAP. in. 



ing the muscles to the bones; 2. Areolar tissue, which is so 

 extensively diffused throughout the body, at once separating and 

 uniting neighbouring parts ; 3. Cartilage, fibro-cartilage, and bone, 

 which enter immediately into the construction of the skeleton ; and, 

 lastly, synovial and serous membranes, being peculiar arrangements 

 of tissue admirably suited to facilitate motion. 



FIBROUS TISSUE. 



Under this head anatomists range two kinds of texture, resem- 

 bling each other only in the fact that they present to the naked 

 eye a fibrous aspect, as if they were compounded of a series of 

 bundles of threads or fibres. They differ, however, very materially 

 in colour, in physical properties, in ultimate structure : the general 

 purposes which they serve in the animal oeconomy are pretty much 

 the same ; for both are used in connexion with the skeleton, and 

 are concerned in the mechanism of animal motion and locomotion. 

 They are distinguished as, 1. White Fibrous Tissue ; 2. Yellow 

 Fibrous Tissue. 



1. White Fibrous Tissue. When a texture of great strength and 

 flexibility, and of an unyielding nature, is required, either to bind 

 parts of the skeleton together, to cover and protect organs of deli- 

 cate texture^ to unite muscles to bone, or other parts, to compress 

 the muscles of a limb, or strengthen the walls of a cavity, we 

 find white fibrous tissue called into requisition for these purposes. 

 Hence we observe it to assume a great variety of forms, according 

 to the various uses to which it is applied. It occurs, 1, as liga- 

 ments, connected with joints ; 2, as tendons, connecting muscles 

 to bones ; 3, in a membranous form, covering and protecting cer- 

 tain organs, as the dura mater of the head and spine, the tunica 

 albuginea of the testicle, the sclerotic coat of the eye, the fibrous 

 pericardium, the covering of the corpora cavernosa penis, the fibrous 

 sheaths of tendons^ the periosteum of bone, the perichondrium of 

 cartilage, the aponeuroses of the limbs, as the fascia lata, &c. 



When we examine a portion of fibrous tissue taken from any 

 of these sources, we find connected with it a greater or less quan- 

 tity of areolar tissue, which adheres to its outer surface like a 

 sheath. This is the case in all fibrous structures, except those 

 which have a serous membrane connected with them, or those 

 adherent to bone or cartilage. The areolar tissue sinks into the 

 fibrous material, and mingles with its fibres : and, doubtless, it not 



