THE CELL AND ITS ACTIVITIES 15 



summation of the lives of innumerable cells - - some- 

 what as the life of a town or a school is the aggregate 

 of the lives of its members. The life of the body differs 

 from the life of the town or nation in that it is much 

 more completely socialized ; the parts or individual 

 cells work in more complete harmony, and are under 

 more accurate control by the governing power which 

 has its principal seat in the brain. In spite of this, 

 disturbances often occur, and the disease called cancer, 

 in which a group of cells runs riot, growing without 

 proper relation to the rest of the organism and without 

 developing even the necessary means for its own main- 

 tenance, represents anarchy in the corporate system. 

 Cancer tissue is not capable of entering into coopera- 

 tion with the rest of the body. When we say that hu- 

 man life is composite in the manner described, we do 

 not infer that human personality is without its proper 

 and definite unity, though the study -of psychology 

 exhibits to us wonderful complexities of personality, 

 connected with bodily states and with the diverse ac- 

 tivities of the nervous system. With this, however, 

 we are not just now concerned. 



3. Since cells are true units of life, they exhibit all Evolution of 

 the essential vital functions. That is to say, they react 

 to stimuli, they build up and break down, and finally 

 they reproduce. The origin of new cells is always 

 from the division of preexisting ones, so far as we have 

 any knowledge ; reproduction is division. No man 

 can make a cell, nor can he say how one came into 

 existence. Professor T. C. Chamberlin makes the 

 ingenious suggestion that prior to the appearance of 

 bacteria (decay-producing germs) it may have been 

 possible for a series of carbon compounds to evolve, 

 leading up to those complex enough to be the seat of 



