The Intimate Causes of Old Age. 207 



that the brain is like a photographic plate or film. 

 Whereas, what we know of the brain neurons leads us to 

 conclude that there is little or no analogy of tliis kind ; 

 that the building up of a personal intellect bears no 

 resemblance to photography. A human intellect, with 

 memory, implies a corelated, cooperative effort on the part 

 of many millions of cells, acting together, 2>ooling their 

 cell lives about a personal axis. Each cell is thus stimu- 

 lated to live in a certain way, rather than stamped by a 

 photographic picture from without. The cell contents, or 

 sentient substance of each cell, is in a state of constant flux 

 and mutation, replaced every second by fresh particles, not 

 " fixed " as in a photograph. An intellect is, therefore, a 

 certain manner or mode of cell life relatively to the other 

 cells of the entire brain, not a series of photographic 

 plates packed away in the brain. The instances of 

 double personality, double consciousness, and recurrent 

 personality, indicate that when, from any cause the first 

 or former personality ceases, a second personality may be- 

 gin, as if about a new personal axis, and go on to develop 

 another intellect of the brain cells, quite as if the first had 

 never existed. 



It is, therefore, fair to infer that if at the age of fifty or 

 sixty, it was the custom of, human beings to enter on a 

 new cycle of brain life, and there were opportunity and 

 social field for it, a new axis of personality would slowly take 

 the place of the old, and that the cell life of the brain would 



