THE NERVOUS SYSTEM OF MAN 1 47 



limits in a manner similar to the processes of 

 reproduction or metabolism. The method fol- 

 lowed in this book, should not make one lose sight 

 of the fact that none of these basal laws acts in- 

 dependently. They are inextricably bound up in 

 a living organism which is the unit. Each law 

 has no significance apart from this relationship — 

 all are necessary to form life. 



What are the several aspects of this primary 

 law of protoplasm and the bearing of the more 

 recent discoveries? Does this form of analysis 

 help one to gain a better understanding of his own 

 mental processes? The current views concerning 

 the organization of the structures through which 

 this phase of vital activity takes place enable us 

 to gain a new picture of its probable method of 

 working. Some of the prominent popular hy- 

 potheses will find no place in this discussion be- 

 cause they have really been supplanted. Un- 

 fortunately the complexity of the nervous system 

 is such that it requires a certain amount of techni- 

 cal description before one can properly appreciate 

 the significance of the generalizations that science 

 has made. Those who resent this form of an- 

 alysis should remember that mind and body are 

 intimately associated. 



The simple animal cell, the ameba described 

 on page 36, is able to eat, carry on the processes 

 of metabolism, respiration, excretion and repro- 



