CHAPTER IV 



Nerve cells and nerves Spinal cord Motor and 

 sensory nerves Reflex action The brain The 

 Amphioxus and its nervous system Fish The 

 Lamprey and its brain The basal or instinctive 

 ganglia The development of the cerebral cortex 

 The Mud-fish The Stickleback, Salmon, Perch, 

 instinctive processes of, shown in traits of char- 

 acter Their existence depends on presence of basal 

 ganglia Amphibians, brain of Location of centre 

 of instinctive movement Reptiles, sense organs 

 of Birds. 



IT has been shown above that the effective 

 working of the living substance forming the 

 body of a nerve cell depends on its metabolic 

 properties, whereby the cell is kept primed with 

 working energy. One of the functions of these 

 charged elements is to respond to the streams 

 of energy which reach them through sensory 

 organs, and to transmute this energy into pur- 

 posive instinctive action. Automatic action 

 of this kind is all that is necessary for the pre- 



