454: MOVEMENTS. 



is, of course, the muscular fibre or fibrilla ; but we also find 

 in the substance of the muscles certain anatomical elements, 

 not peculiar to the muscles, and merely accessory in their 

 function, but none the less necessary to their proper consti- 

 tution. For example, every muscle is composed of a number 

 of primitive fasciculi ; but these are gathered into secondary 

 bundles, which in turn are collected into bundles of greater 

 and greater size, until, finally, the whole muscle is enveloped 

 in its sheath, and is penetrated by a fibrous connective sub- 

 stance. We find, probably, in the muscles, the best illustra- 

 tion of the structure of what is known as the connective 

 tissue. 



Connective Tissue. We have already had occasion to 

 refer to certain of the elements of connective tissue, more 

 especially the inelastic and elastic fibres. In this connection 

 we shall treat specially of the connective tissue of the mus- 

 cles ; but our description will answer for almost all situations 

 in which fibrous tissue exists merely for the purpose of hold- 

 ing parts together. In the muscles we have a membrane 

 holding a number of the primitive fasciculi into secondary 

 bundles. This is known as the perimysium. The fibrous 

 membranes that connect together these secondary bundles 

 with their contents are enclosed in a sheath enveloping the 

 whole muscle, sometimes called the external perimysium. 

 The peculiarity of these membranes, and their distinction 

 from the sarcolemma, is that they have a fibrous structure 

 and are connected together throughout the muscle, while 

 the tubes forming the sarcolemma are structureless, and each 

 one is distinct. 



The name now most generally adopted for the tissue un- 

 der consideration is connective tissue. It has been called 

 cellular, areolar, or fibrous, but most of these names were 

 given to it without a clear idea of its structure. Its prin- 

 cipal anatomical element is a fibre of excessive, almost im- 

 measurable, tenuity, wavy, and with a single contour. These 



