156 SENSORIAL FUNCTIONS. 



members of the mammalia tribes. The porpoise is also 

 another of this class. These animals, are obliged of 

 course, to come up to the surface to breathe, the action 

 called spouting being merely the expiration of the air from 

 the lungs, preparatory to the inspiration of another por- 

 tion, and by which a quantity of water is thrown above 

 the surface. 



PART V. 



SENSORIAL FUNCTIONS. 



468. THE Sensoricd Functions are those which belong 

 to the brain, as the general source of sensation and 

 perception. The systems we have heretofore been occu- 

 pied in describing, consisting of the mechanical and ani- 

 mal functions, are only the foundations of the higher 

 order ( f faculties which animals, and especially man are 

 destined to exercise. 



469, Brain and Nerves. The functions of sensation, 

 perception, and voluntary motion, require the presence of 

 an organized animal substance, which is endowed with 

 very remarkable properties, and which is known to 



What are seasonal functions ? What is the foundation of the sensorial 

 functions ? 



