42 QUALITY OF GREY MATTER. 



brain the thalami optici and corpora 

 striata serves the still higher functions, 

 the " instinct "-ive, viz., those of sub- 

 consciousness, such as dreams, visions, 

 sleep-talking, sleep-walking, habits and 

 acquired reflexes ; is of a still higher quality, 

 and responds to still higher and more 

 complex stimuli, such as the higher bodi'y 

 and lower mental calls and promptings. 

 And the grey matter of the higher brain 

 the cortex or surface of the hemispheres- 

 serves the most important of all functions, 

 viz., those of full consciousness and the 

 highest mental functions ; is of the highest 

 quality, and responds to the highest kind 

 of stimuli, such as social and mental 

 promptings and impulses. 



As well as rising in position and increasing 

 in quantity, the grey matter also improves 

 in quality, as every other organ in the 

 body does, with the importance of the 

 function it has to perform. The higher 

 the function the higher the position and 

 quality of the grey matter ; in other words, 

 the higher the position of the grey matter 

 the higher the function it performs. This 

 law rules even in the grey matter of the 

 hemispheres of the brain. Also the greater 

 the quantity of grey matter, that is, the 



