INTRODUCTION, 39 



sideration of such properties and effects as are 

 manifest to observation. 



A summary consideration of the functions and organs of 

 the Animal Body, and of the various degrees of their 

 comp osition. 



After what has been said in relation to the orga- 

 nic elements of the body, of its chemical principles, 

 and of its active forces, it only remains to give a 

 compendious idea of those functions in detail which 

 are proper to an animal body, and of the organs ap- 

 propriated to their use. 



The functions of the animal body are divided into 

 two classes : 



1. Those peculiarly and exclusively animal, name- 

 ly, sensibility and voluntary motion. 



2. The mere vital or vegetative functions, which 

 are common to animals and plants, viz., nutrition 

 and generation. 



Sensibility resides in the nervous system. 



The most extended of the external senses is that 

 of feeling, which is seated in the skin, a membrane 

 enveloping the entire body; this is traversed in 

 every direction by nerves, which conduct the excite- 

 ment of this sense to the sensorium, the final fila- 

 ments of which are spread into papillse upon the 

 surface of the true skin, but guarded there and 

 overspread by the epidermis, and in the different 

 species by other insensible teguments, as liair^ 

 shells, $r, 



