FUNCTIONS OF/ RELATION. 71 



36. In acting upon the tissues of the organs, the blood loses 

 a part of its vivifying properties, and in order to regain them, 

 requires to be brought into contact with the atmospheric air, 

 which contact constitutes the phenomenon of RESPIRATION. 



37. Finally, the materials separated from the substance of the 

 organs, in consequence of the nutritive movement, are carried 

 along by the blood, and are afterwards separated and rejected from 

 the system in the form of liquids, or of vapours. These acts, 

 which are in a measure, the completion of the nutritive process, 

 bear the general n imes of EXHALATION and SECRETION. 



38. To recapitulate ; we see then that the functions of nutri- 

 tion are constituted of several series of phenomena, each having 

 its seat in different organs, and that these different acts are : 



1st. Digestion; 

 2nd. Absorption ; 

 3rd. Circulation; 



4th Simultaneous decomposition and recomposition of the 

 organs of nutrition, properly so called ; 

 5th. Respiration; 

 6th. Exhalation and Secretion. 



LESSON VII. 



FUNCTIONS OF RELATION Nervous system and sensibility. 

 FUNCTIONS OF RELATION. 



1 . The phenomena of animal life or life of relation depend upon 

 two faculties : that of sensation and that of motion. 



2. These faculties, which do not exist in an equal degree of 

 perfection in all animals, are wanting in vegetables. They are 

 the result of an action of two apparatuses ; the apparatus of sen- 

 sations and the apparatus of motion. 



3. The apparatus of sensations is composed of the nervous 

 system and the organs of the senses. 



36. What is the obje< t of respiration ? 



37. What comoletes the phenomenon of nutrition? 



38. What nre the several functions of nutrition? 



1. Upon what do the phenomena of the functions of relation depend? 



2. Do the faculties of sensation and motion exist in an equal degree in 

 1J animals? Do they exist in vegetables? Upon what do these faculties 

 depend ? 



3. Wh^t parts compose the apparatus of sensation*? 



H 



