42 INTRODUCTION, 



which appear to be continuations of the former, and 

 are denominated tendons. 



The structure or configurations of the articulated 

 surfaces of these hard parts restrict their motions 

 to certain directions, and they are further restrained 

 by bundles of strong and unyielding cords called 

 ligaments, attached to the sides of the articula- 

 tions. It is according to the various dispositions 

 of such bony and muscular apparatus, and accord- 

 ing to the form and proportion of the limbs result- 

 ing from them that animals are able to execute the 

 varied motions which enter into the exercise of 

 walking, leaping, flying, and swimming. 



The muscular fibres appropriated to digestion 

 and circulation are not subservient to the influence 

 of the will. Nerves, however, are attached to 

 them, but, as before observed, conformed and ar- 

 ranged with the evident intention of withdrawing 

 them almost totally from this influence. It is only 

 in the paroxysms of passion, and other violent af- 

 fections of the mind, that volition bursts as it were 

 through the barriers, and extends its empire over 

 these forbidden regions ; but the effect of this irre- 

 gularity is, for the most part, to produce nothing 

 but disorder and confusion in the functions of vege- 

 tative life. These functions are likewise unaccom- 

 panied by sensations, except in a state of indispo- 

 sition. Digestion is usually carried on without the 

 consciousness of the animal. 



The food, divided by the jaws and teeth, or 



