irCTRODUCTION. xvii 



investing these cartilaginous ends; fourthly, lateral and other 

 ligamentous chords, running from one bone to the other, to 

 strengthen the connexion ; fifthly, a fluid resembling the white 

 of egg, exuded from the internal surface of the capsule, for 

 the purpose of lubricating the cartilaginous ends, and preserving 

 them from friction. Although such is the general composition of 

 this third kind of joint, we find it varied in every particular in- 

 stance to suit the intentions of nature : exciting our admiration no 

 less for its inimitable beauty or construction than for its won- 

 derful power and effect. 



Ending our account of the passive mechanism of locomotion, 

 we come to consider the active powers or means by which the 

 machine is set in motion. Little, perhaps, would that person 

 imagine, who contemplated simply the dead body, that muscle or 

 flesh possessed such capability ; much less would he suppose its 

 power to be of that wonderful nature which experience has 

 taught us that it is. Even the anatomist himself discovers 

 nothing in the structure of a muscle to account for such pro- 

 perties ; but is compelled, after the most tedious and elaborate 

 research, to ascribe them to something he cannot explain, de- 

 pendent upon the presence and exercise of the vital energy. 

 Only by calling in this mysterious power to his aid, can he pre- 

 tend to offer any reason why a piece of flesh that would of itself 

 be torn asunder by the weight of a few ounces, should, in a 

 living state, be capable of lifting and sustaining a hundred or more 

 pounds ! 



A muscle, anatomically examined, is found to consist simply 

 of a congeries of longitudinal fibres, disposed in packets or 

 bundles, severally encased in cellular membrane, and by the 

 same material connected altogether into one solid body. These 

 fibres have, superficially viewed, the appearance of being single 

 and indivisible : through microscopic aid, however, we learn, 

 that not only are the packets made up of bundles of fibres of 

 smaller and finer mould, but that even their component fibres are 

 themselves packets of similar composition ; in which way we 

 become continually foiled and disappointed in our researches 

 after the ultimate or original fibre, whereunto no investigator has 

 hitherto arrived. 



c 



