THE INFLUENCE OF NUTRITION AND 

 THE INFLUENCE OF EDUCATION IN 

 MENTAL DEVELOPMENT 1 



By F. W. MOTT, M.D., F.R.S. 



In the last lecture I pointed out to you that the brain consists of 

 innumerable nervous units or neurones and that these nervous 

 units or neurones are collected into groups, systems, and com- 

 munities having different functions, but that broadly speaking 

 they form three great groups or classes, viz. (i) efferent sensory 

 chains of neurones ; (2) efferent motor chains ; and (3) associa- 

 tion chains of neurones (fig. 1). A neurone consists of a nerve 

 cell and all its branches ; one branch forms a nerve fibre which 

 is called the axon because it forms the central axial core of the 

 nerve, the other branches, like those of a tree, are called den- 

 drons. The grey matter of the cortex covering the surface of 

 the brain which is the seat of consciousness consists of countless 

 millions of nerve cells and processes and thus gives it its grey 

 appearance. 



Innate Potentiality of the Neurones, and Brain 



Development 



In the child's brain before birth these cells are packed closely 

 together, and at one period they have no processes ; as the 

 brain develops and grows these cells, which are termed neuro- 

 blasts (neurone-formers), send out processes which, extending 

 and branching like a tree, lead to an increased complexity of 

 structure. This capacity to grow and develop is inherent in all 

 the neuroblasts of the brain, but in order to grow and develop 

 they must be fed by the blood with suitable food. Just as some 

 individuals with abundance of food-supply do not develop and 

 grow because they are unable to take it, or if they do to 

 assimilate it, so it is with the neurones; if there is an inborn 

 failure to take up from the blood and assimilate the food sup- 

 plied, they will not develop and grow. 



1 Third Chadwick Trust Lecture, continued from Science PROGRESS, October 



1913. 



460 



