PROPERTIES OF ANIMAL BODIES. 103 



37. fThe sensorial functions are sometimes called the 

 functions of relation, because it is through them that we 

 hold communication with the external world. They com- 

 prise the sensations, intellectual operations, and voluntary 

 motions^ (It is the sensorial functions that raise man above 

 all other animals| In proportion as they are more or 

 less perfect, organized beings ascend or descend in the 

 scale of existence. In the lower animals, they are limit- 

 ed to the circle of physical wants ; but in man, they con- 

 fer moral and intellectual faculties, which are his noblest 

 attributes. 



38. These functions have the brain as their common 

 centre. They can be improved to an almost indefinite 

 degree by education and habit. We see this in the perfec- 

 tion which some of the senses acquire when others are lost ; 

 in the gigantic intellect of a Newton or a Locke, whose 

 mental efforts at first were probably as weak as those of 

 other men. In all such cases, individuals acquire superi- 

 ority chiefly by education and constant practice. 



Questions. How is living animal matter distinguished from dead ? 

 What properties are possessed in common ? What are th<3 phenomena 

 of life owing to ? What developes the chick ? What properties does 

 living matter possess ? What is understood by the sensitive powers ? 

 the motive ? the alterative ? What characterizes animals provided 

 with a nervous system ? How many kinds of sensibility are there ? 

 What is meant by general sensibility ? by special ? What is tho 

 common centre of sensibility ? What is perception ? What is organic 

 sensibility ? Are the internal organs sensible to the presence of their 

 contents ? How are such parts affected by disease ? What is con- 

 tractility ? What element possesses it in a great degree ? How many 

 kinds of contractility are there ? When is a limb said to be paralytic ? 

 When in spasm ? What are the alterative powers ? What their use ? 

 Is the body under the influence of chemical laws f-" What are the 

 physical properties of the animal tissues ? What office does elasticity 

 perform ? Describe its operation in cartilages, arteries, &c. What 

 are the uses of flexibility and extensibility in the animal body ? What 

 is imbibition ? Do the serous membranes absorb ? What experiment* 



