162 PRESIDENT’S ADDRESS—SECTION J. 
portions of the brain; in an infant it is as much as 15 to 1, 
whilst in the adult it is only 7 to 1. It has been already 
noted that although nerve cells and fibres exist in the cerebrum 
at birth, yet that they have not in any way become co-ordinated 
in function, and that the cerebrum of an infant is practically 
a tabula rasa as regards associated action. The infant, there- 
fore, notwithstanding its proportionately large cerebrum, is a 
most helpless object, and has no power of adaptation. The 
existence of the cerebrum, however, ensures the production of 
“ activities,” for it is an inherent attribute of living cells to 
function when nutrition has reached a certain point, and in the 
case of nerve-cells a discharge or nerve-wave becomes impera- 
tive. As Bain points out, there is always “a spontaneous or 
self-moved commencement, followed by the gradual attempt to 
direct it into definite channels. The rule seems to be that activity 
is always prior.” If we look upon the cortex cerebri as posses- 
sing pre-eminently the power of registering impressions for 
future psychic use, it becomes evident why it should precede in 
development other portions of the brain. An inherent attribute 
of this structure is that it is highly receptive and plastic. As 
the body continues to grow, other portions of the brain proceed 
in development pari passu, and each in its functioning in- 
fluencing the nutrition of the other. So that in estimating the 
laying down of the foundations of a psychic life, and the raising 
of its superstructure, we cannot afford to ignore the influence 
of any portion of the organism. In this connection reference 
may be made to the intimate relationship that appears to exist 
between the development of the museular system and the in- 
tellectual powers. In the feeble-minded the imperfect develop- 
ment of the muscles of the limbs is most obvious, and the move- 
ments are awkward and ungainly. This may be the result of an 
inherent want of receptivity and plasticity in the cortex, not 
allowing of the beneficial efforts of reciprocal stimulation on 
other tissues physiologically connected with it, as was noted was 
the effect of a lesion in the visual area of the cortex on the optic 
thalamus ; or the result may be due to feebleness in other parts 
of the brain and organism failing to supply the requisite stimula- 
tions for registration in the cortex. If, therefore, during the 
first few years of a child’s life we see it growing in stature 
and in muscular strength, we may rest assured that the cerebral 
cortex is also functioning in a normal and healthy manner. 
During this lustrum no attempt should be made to attain any 
acquisition, the active element of which is not already in ex- 
istence. “ Language (spoken),” as Bain points out, “seems the 
most precocious of all acquirements, being usually in advance of 
the manual capabilities. The activity of the eye is also very 
early, and the cognition of visible movements, magnitudes, 
forms, and all space relations, proceeds rapidly. This is the 
