LIVING BODIES AND CELLS 13 



which it divides ; and so we say that the new cell inherits 

 the peculiarities of the parent. This process may be 

 carried on very rapidly ; and a new cell may be produced, 

 and itself become divided, in a few hours. 



Anything that moves, and eats, and reproduces itself by 

 means of its own power, is alive ; and so the cells of the 

 body are alive in the fullest sense of the term. 



Diagram of the division ot a cell. 



7. Other distinctions between the living and the dead. 



Many living bodies will show some spontaneous movement in response 

 to a prick or a blow, or other irritation. Certain causes, as a low tem- 

 perature, may suspend the ability to respond to an irritation, but it will 

 return when warmth is applied. A lifeless thing never puts forth effort, 

 no matter how much it is irritated. 



Decay never occurs in cells while they live ; but after death disinte- 

 gration soon begins, even if no outside power acts upon the cells. On 

 the other hand, a body which has never been alive usually changes very 

 slowly or not at all, unless acted upon by an outside power. 



8. Relation of cells. In the body formed by the cells 

 there exists a controlling spirit of life, which dominates the 

 whole. When all the cells are obedient to its influence 

 the body as a whole is alive ; but if the cells are not 

 obedient, the body as a whole is dead, although each 

 separate cell may remain alive. For example, a blow 

 upon the head may disturb this controlling influence so 

 that it cannot tell the cells how to act. Then they instantly 

 stop work, and the body drops dead. Yet each cell may 

 remain alive for minutes or hours, just as each soldier may 

 remain alive after an army has been disbanded. 



