316 



together ; the fasciculi of fibres are inclosed in common sheaths, and 

 these unite, in the same manner, into masses varying in size, and the 

 union of which forms the muscles; fat seldom accumulates in the cellu- 

 lar tissue which connects together the smallest fasciculi; it collects, in 

 small quantity, in the interstices of the more considerable fasciculi; last- 

 ly, it is in rather greater quantity, around the muscle itself. A lympha- 

 tic and aqueous vapour fills these cells, maintains the suppleness of the 

 tissue, and promotes the action of the organ, which a fluid 01 more con- 

 sistence would have impeded. 



The greater number of muscles terminate in bodies, in general round, 

 of a brilliant white colour, that forms a striking contrast with the red co- 

 lour of the muscular flesh, in which one of their extremities is imbedded, 

 while the other extremity is attached to the bone and is lost in the peri- 

 osteum, though the tendons are quite distinct from it. The tendons are 

 formed by a collection of longitudinal and parallel fibres ; their structure 

 is more compact than that of the muscles, they are harder and apparently 

 receive neither nerves nor vessels; they consequently possess but a very 

 inferior degree of vitality; hence they are frequently ruptured by the ac- 

 tion of the muscles. The muscular fibres are implanted on the surface of 

 the tendinous cords, without being continuous with the filaments forming 

 the latter; they join them in a different manner, and at angles more or 

 less obtuse. 



The tendons, in penetrating into the fleshy part of the muscles, expand, 

 become thinner, and form thus the internal aponeuroses. The external 

 aponeuroses, independent of the tendons, though the same in structure, 

 differ from them only in the thinness and greater surface of the planes 

 formed by their fibres. At one time, they cover a portion of the muscle 

 to which they belong; at another, they surround the whole limb, furnish- 

 ing points of insertion to the muscles; they prevent the muscles and their 

 tendinous cords from being displaced; in a manner, direct their action, 

 and increase their power, in the same way as a moderately tight girdle 

 adds to the power of an athletic. 



enveloping cellular snbstance, experience in consequence a contraction in proportion 

 to the nervous excitement. In this case we must suppose a certain influence to emanate 

 from the connecting medium to the muscular fibre, without any other communication 

 than that of contact or contiguity. If, on the other hand, we adopt the latter alternative, 

 and believe that an order of capillary vessels of great tenuity enter into the structure 

 of the muscular fibre, and that the voluntary and organic nerves which blend with the 

 capillary vessels also proceed to, and terminate in this structure, we may further con- 

 clude and, indeed, the conclusion will necessarily follow, that the muscular fibre is 

 composed of a certain order of capillary vessels, and of the terminations of the ganglial 

 nerves (which nerves we must suppose to supply, and to terminate with these capilla- 

 ries, as they are found to envelope, and to be distributed to the muscular and internal 

 coats of the larger ramifications or trunks of the vessels whence the capillaries are sent 

 off) with the extremities of voluntary nerves which are so abundantly supplied to mus- 

 cular parts. Having considered that the muscular fibre is formed from this combination, 

 me have not data whence we can farther infer its intimate nature, or the extent to 

 which each of these systems contributes to its formation in the voluntary muscles. We 

 may suppose, however, that the functions of these textures differ according as either of 

 the constituents which we have now assigned them predominate in their constitution, 

 (see Note at p. 17.) The observations of Mr. Bauer, we may state, seem to support the 

 view we have now offered. Copland. 



See APPENDIX, Note F F, for further observations on this subject, and on Irrita- 

 bility. 



