156 PRESIDENT’S ADDRESS—-SECTION J. 
Whilst there is considerable definiteness in allotting functions 
to the different sensory spheres, this is not the case with the 
association areas. The frontal association area appears to have 
to do with the capacity to combine the attention with personal 
motives for the regulation of conduct. In disease of this area 
many observers report an alteration in the personal character- 
istics of the individual. The function again of the occipito- 
temporal association area would appear in the same way to be 
largely associated with great intellectual power. This should 
not be surprising, as the larger development of this area is 
pre-eminently characteristic of man. As Dr. Ireland writes in his 
review of Flechsig’s work: “Man owes his mental superiority 
not only to the larger mass and surface of the brain, but also 
to his greater posterior association centres, which enable him 
to associate all his conceptions with words, and then to clothe 
them with words. His capacity to utter these words rests upon 
the larger development of his third temporal gyrus, and also of 
a part of the sensation sphere, which last is not nearly so well 
developed even in the highest apes.” 
Although the cortex cerebrt may be mapped out into areas 
having more or less specialised functions, yet for correct mentali- 
sation it is absolutely necessary that they should all function 
co-ordinately, or be in intimate association with one another, 
This appears to be largely brought about by certain structures 
in the cortex, called pyramidal cells and neurons. These cells, 
although all over the cortex, vary in size, being largest in the 
sensory spheres, but their function appears to be the same 
wherever they exist. These pyramidal cells and neurons are 
formed in the cortex by the time that the child is born, so that 
the adult does not possess any larger number than the immature 
infant. The difference between the two consists in the increase 
in size of the cell, and the greater production of processes or 
fibres from them. If these cells are once destroyed they are 
never renewed ; this does not apply to the processes. The most 
remarkable feature of the neurons is the process called the 
“apical dendrite,” which is developed from the end pointing to- 
wards the surface of the brain. The main branches run directly 
outwards and then divide into numerous fibres running parallel 
with the surface. These finer branches especially present a 
serrated appearance, the lateral processes being sometimes called 
“ vemmules,” and it is these which have considerable recuperative 
power after injury. The suggestive name of “ association fibres” 
is given by physiologists to these apical dendrites. An im- 
portant anatomical fact is that these dendritic processes never 
anastomose or form organised connections with those of other 
neurons. They become contiguous, but not continuous. Quite 
recently a view has been held that the functioning of these 
dendritic processes is due to a certain power of extension and 
