PRESIDENT’S ADDRESS—SECTION J. 161 
poisoning are much the same as is seen after pathological 
fatigue, namely, disappearance of the gemmules and irregular 
moniliform enlargements of the dendrites. It is evident, there- 
fore, that all attempts at teaching should at once be discontinued 
upon a child showing any of the signs of mental fatigue and 
exhaustion, depicted by Warner in his book on Mental Faculty. 
Education to be a science ought to harmonise as far as pos- 
sible with what is known respecting the development of the 
anatomy and physiology of the brain. Bain, in his Education 
as a Science, urges the necessity for this harmony, and points 
to the educational value of certain subjects at varying ages. It 
has been seen that the spheres of sensibility, bodily, visual, and 
auditory, appear on the scene first, and reach a certain degree 
of organisation even at birth. These are the sites in which 
sensations acquire a psychic value, and become data for future 
use. All mental functioning must necessarily depend, first, on 
the data supplied, and, secondly, on the way in which these data 
are grouped and associated in ever-increasing intricacy as long 
as the possibility of acquiring knowledge lasts. Considering also 
that the child differs from other young animals in inheriting 
but few organised experiences or so-called instincts, it follows 
that the experiences it acquires are more individualistic, and all 
help to form its character. Owing to this, .all the child’s 
activities, muscular and otherwise, have an educational value, 
and should be respected as such, especially in its early years. 
To interfere with these by any artificial methods must always 
be a matter of some delicacy, and may be fraught with danger 
unless in skilled hands. For convenience of consideration, the 
period of growth and development may be divided into three 
lustra, each distinguished in a general way by certain cortical 
cerebral anatomical characteristics. 
The first lustrum is characterised by a comparatively greater 
development of the spheres of bodily, visual, and auditory sensi- 
bility. And it cannot be too constantly borne in mind by those 
who have to do with the young that another characteristic of 
this period is that during the first seven years of a child’s life 
an extraordinary amount of brain growth is going on. It is 
stated that at birth the brain weighs from 15 to 16 ozs., whilst 
at two years of age it weighs from 35 to 40 ozs., and at seven 
about 45 ozs., the adult brain at twenty weighing from 48 to 
50 ozs. At seven years of age the general body weight ought 
to have increased ten times, and at twenty twice that amount. 
This all means a vast production and expenditure of force, and 
that a child’s powers during the first seven years of its life are 
quite sufficiently taxed by simply living, and growing, and 
receiving the natural impressions that pertain to a well-regu- 
lated, healthy environment. Another peculiarity of the young 
brain is the large preponderance of the cerebrum to the other 
L 
