538 SECTIONAL TRANSACTIONS.—J. 
The essential bases of language : 
(a) Spontaneous expressions of feeling. 
(b) Spontaneous babblings and practice in sound making. 
(c) Association of sounds heard with feeling, objects, or general 
situations. 
Early effects of social influences. 
Individual differences indicative of future development occur as early 
as 1 and 2 months. (Slower speech development of A and B as compared 
with Y indicated before 2 months.) 
From 4 to 9 months practising of new sounds very important. 
The ‘ understanding ’ of meaning of some words clearly established at 
6 or 7 months. 
‘ Understanding’ and ‘ expression’ far from identical. For expression 
a different word from the word heard and understood may be used for the 
same thing. 
Prominence of feeling or conational aspect of early speech. 
Importance of imitation, especially from 14 or 14 years onwards. 
The generalisation of meanings; the specialisation of words. 
Does the child originate words ? 
Special characteristics of the period 13 to 2 years. Use of negative. 
First questions. 'Two- or three-word sentences. 
The great discovery— Things have names.’ 
From 2 to 3 years. Words indicating spatial and temporal relations. 
Testing by experiments the understanding of prepositions. Subordinate 
sentences : Why and Because. All forms of sentence structure now used. 
Joint Discussion with Section I (Physiology) on Disorientation and 
vertigo (10.30). 
Dr. J. T. MacCurpy. 
Dependence of spatial orientation on balancing system. (Examples.) 
When latter disturbed, get disorientation and a secondary confusion 
(psychological), which produces failure to recognise objects. 
Under normal circumstances balance depends on postural and righting 
reflexes. These are stimulated by changes in otolith organs, semicircular 
canals, muscle tensions, deep pressure and vision. ‘The muscular system 
is the most important (Garten’s experiments). It has incredibly low 
threshold and speed of reaction and is unconscious. There is probably 
awareness only for response, and for that only when exaggerated, i.e. when 
balance is lost ; awareness is for disequilibrium, not equilibrium. (‘ Falling’ 
is a visual perception.) Disequilibrium is sensed by vision and vestibulo- 
proprioceptive organs. 
This is illustrated in flying, which demands an acquired balancing reaction. 
Until this is gained visual orientation is difficult or impossible (Data). 
Innate balancing reactions are made to actual direction and value of g, but 
visually to aeroplane. Hence conflict and giddiness until aeroplane is 
treated as part of body (acquisition of manipulative control). Conflict 
leads to excessive proprioceptive stimuli because reaction does not abolish 
stimulus as in effective balancing. 
This leads to nausea via excessive and incoordinate reflex response. 
Two types of sensitiveness, one to increase in value and one to change in 
direction of g. Normal response to increased g (alighting on ground when 
jumping) is tension in extensors and rigidity of abdominal walls to prevent 
displacement of viscera. If rapid and effective, diaphragm does not move, 
