326 APPENDIX. 



Flesh. The remaining substance concerned in the 

 connection of the bones is the flesh, or muscular fibres. 

 It is by this means that the upper, as well as the lower 

 extremities, are chiefly connected with the trunk, or 

 body; these parts requiring great strength, as well as 

 general motion, it being by means of the muscles that 

 all the motions of the system are carried on. 



Tendons. Many of the muscles contain, besides flesh, 

 a substance analogous to ligament, through the medium 

 of which they are attached to the bones, which are termed 

 tendons. In most instances the muscles and tendons 

 gradually replace each other, the thick part, being red 

 flesh, gradually terminating in cords of shining white ten- 

 don, the extremity of which is attached to a movable 

 bone. The tendon of the heel, and the muscle of the 

 calf of the leg, is a good example. 



Muscles and tendons are composed of bundles of fibres, 

 which may be unraveled to extreme minuteness, when 

 what appears to the naked eye as a single fibre, when 

 placed under the microscope appears like a chain of infi- 

 nitely small globular particles. 



Nerves. But though the muscles are the immediate 

 organs of motion, they are dependent for their powers of 

 contraction and relaxation upon the nerves, with which 

 they are every where numerously supplied. The nerves, 

 when examined by themselves, appear in the form of white 

 inelastic cords, or threads ; and, when traced to their ori- 

 gin, are found to issue from the brain, or spinal marrow, 

 the latter being considered an elongation or continuation 

 to the former through the spinal canal. The trunks of 

 the nerves are subdivided into branches, and these, again, 

 into filaments not larger than hairs, which enter into the 

 muscles and all other parts having sensation, being, as it 

 were, lost in their substance ; that is, they become too 

 minute for detection by the senses, though, in every case 



By what means are the limbs chiefly connected to the trunk? What are 

 the tendons ? Where are the tendons attached ? What are muscles and 

 tendons composed of? By what power do the muscles act? From what 

 parts do the nerves issue ? What are the nerves the organs of? 



