CHAPTER SIX 



THE INDIVIDUAL 



1. WE always think of the individual as the natural Thein- 

 unit of life. The very word implies indivisibility in the ^fofl 

 sense that the whole is something different from a mere 

 aggregation of its parts. This idea is not without sup- 

 port from analogy. The atom, the molecule, even the 



cell, - - each possesses this property of individuality. 

 They do things as wholes, which their parts could not 

 do separately. They behave as machines, the several 

 parts of which cooperate for a common purpose. Surely 

 the individual animal or plant also so behaves ; is a 

 workable machine, a whole which may not be divided 

 without destroying its characteristic functions. 



The fact that reproduction is division has no bearing 

 on the argument. We have seen that in the many- 

 celled animals the reproductive cells are set aside, and 

 are not part of the machine, except in an indirect sense. 

 Therefore it is reasonable to say that the production of 

 young is no infringement on the wholeness or individ- 

 uality of the parent. 



2. Nevertheless, upon further inquiry, it becomes The in- 

 hard to define the individual in a biological sense. It ^^o 

 would be simple to say that the individual is the prod- define 

 uct of a single fertilized egg cell. This is ordinarily but 



not necessarily the case. Dr. Jacques Loeb made some 

 experiments with sea-urchin eggs, placing them soon 

 after fertilization in sea water greatly diluted with dis- 

 tilled water. In this mixture the eggs took up so much 

 water that their enveloping membranes burst and part 

 of the protoplasm escaped in the form of a globule or 

 drop. The eggs were then returned to normal sea 

 water, and in due course developed. When the ex- 



37 



