FUNCTIONS OF GREY MATTER. 41 



a brain, and improved in quality. Wherever 

 present, when excited by appropriate 

 stimuli, it manifests the phenomena called 

 mental ; and these phenomena vary with 

 the position and quality of the grey matter 

 manifesting them. 



The illustration* shows the spinal cord ; 

 its upper end (medulla oblongata) ; the 

 lower brain (optic thalami and striated 

 bodies) ; and the upper brain, the cortex. 



As pointed out by Dr. Schofield, the 

 grey matter in the lower part of the spinal 

 cord serves the very low mental functions, 

 viz., those of common reflex action ; is 

 of very low quality, and responds to very 

 low kinds of stimuli, viz., those conveyed 

 from the skin, the muscles, and viscera. 

 The grey matter in the upper part of the 

 spinal cord the medulla oblongata 

 serves functions that are higher and more 

 important, the sub-" instinct "-ive, viz., 

 those of respiration, circulation, and diges- 

 tion ; is of a higher quality, and responds 

 to higher and more complex stimuli, viz., 

 the calls in the system for oxygen and 

 blood. The grey matter in the lower 



A copy of the diagram in Dr. A. T. Schofield's excellent 

 treatise on " The Unconscious Mind." He has kindly 

 allowed me to make use of it. 



