34 



INTRODUCTION TO NEUROLOGY 



represented in the innate neuro-muscular organization. Every 

 single act which the animal is capable of performing has its 

 mechanism provided in the inherited structure. But higher 

 animals may learn by experience to combine these simple ele- 

 ments in new patterns. The higher correlation centers serve this 

 function. The presence and general arrangement of these 

 centers is, of course, also determined in heredity; but the partic- 



reptiies 



Vertebrate Phylum 



Fig. 4. Two diagrams illustrating the relative development of the 

 invariable and variable factors in the behavior of the articulate phylum 

 and the vertebrate phylum of the animal kingdom. In the articulate 

 phylum the invariable factor (represented by the shaded area) predominates 

 throughout; in the vertebrate phylum the invariable factor predominates 

 in the lower members of the series, and the variable factor (represented by 

 the unshaded area) increases more rapidly in the higher members, attaining 

 its maximum in man, where intelligence assumes the dominant role. 



ular associations which will be effected within them are deter- 

 mined by individual experience, and the building up of these 

 new associations is the chief business of education (see p. 312). 

 In the analysis of behavior and the related neurological mechan- 

 isms the distinction between the innate and the individually 

 acquired factors must always be kept clearly in mind. The 

 failure to do so, and also the failure to distinguish between these 



