II. Muscular movements in man, and their evolution in the infant: a study of movement in man, and its evolution, together with inferences as to the properties of nervecentres and their modes of action in expressing thought


1888.J Muscular Movements in Man and their Evolution. 329’

II. “ Muscular Movements in Man, and their Evolution in the 
In fa n t: a Study of Movement in Man, and its Evolution, 
together with Inferences as to the Properties of Nerve- 
centres and their Modes of Action in expressing Thought.” 
By F rancis W arner, M.D., F.R.C.P., Physician to the 
London Hospital and Lecturer on Botany in the London 
Hospital Medical College. Communicated by Professor J . 
H utchinson, F.R.S. Received June 12, 1888.

(Abstract.)
Movements as signs of brain action have long been studied by the 

physiologist; but before proceeding to give an account of the visible 
evolution of voluntary movement in man, it is necessary to define the 
different classes of movements seen, indicating the criteria by which 
the observer may be guided in the examples before him. Movements 
may be classed according to the parts moving, the time, and the 
quantity of each movement. These are the only intrinsic attributes 
of such acts. If the nerve-centres which send stimuli to tho muscles 
are acting in equilibria, the static outcome is seen in the postures 
resulting in the body ; hence postures are signs of the ratios of action 
in the nerve-centres, and indicate their present state or mode of 
action. Typical postures and movements are described. A variation 
in the ratios of action in the centres leads to visible movement. 
Certain postures and movements are found by experience to corre­
spond to certain recognised brain states. Movements may occur in 
combinations and in series ; special combinations and series of move­
ments determine the outcome of the action of which they are com­
ponent parts. I t is shown that the time of action in the various 
centres thus determines the outcome of the action, and is itself con­
trolled by impressions received through the senses. When movements 
are seen, not controlled by present circumstances, they are probably 
the result of antecedent or inherited impressions; such are called 
spontaneous.

Section II. Evolution of Movements in Man.
The new-born infant presents constant movement in all its parts 

while it is awake, and this is not controlled by impressions from 
without. Graphic tracings of such movements are given. This 
spontaneous movement in the infant appears to be of great physio­
logical importance, and is here termed “ microkinesis.” I t is argued 
that the mode of brain action which produces microkinesis is analogous 
to the action producing spontaneous movements in all young animals, 
and to the modes of cell-growth which produce circumnutation in

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830 Muscular Movements in Man and their Evolution. [June 21,

young seedling plants. I t is argued that as circumnutation becomes | 
modified by external forces to tbe modes of movement termed 1 
beliotropism, geotropism, &c., so microkinesis in tbe infant is replaced 
by the more complicated modes of brain action as evolution proceeds. 1

The conditions of movement are then described, as seen at succes-1 
sive stages of development of tbe child, and it is shown that they 
become less spontaneous, and more under control of stimuli acting 
upon the child from without, while the phenomena termed memory 
and imitation are evolved.

Section III. Properties of Nerve-centres and their Modes of Action.
From observations made, descriptions are given of the modes of 

action and properties of nerve-centres in adult age, such descriptions 
being given in terms implying visible movements. Impressionability, 
imitation, and retentiveness are thus described. Nerve-centres are 
said to be “ free ** when only slightly stimulated. Delayed expression 
of impressions are seen when the visible outcome is delayed after 
the stimulus which produced it. Double-action is said to occur when 
a local effect and a distant one, occur from one impression. Com­
pound cerebral action is said to occur, when the study of the visible 
movements indicates that successive unions of centres are in action, 
leading to a visible outcome well adapted to tbe primary stimulus 
which produced the series. When a slight stimulus leads to a spread­
ing area of movements producing considerable force, the phenomenon 
is termed reinforcement.

From observations made, two hypotheses are put forward. It is 
suggested that when a well co-ordinated movement follows a slight 
stimulus, the impression produces temporary unions among the 
centres, preparing them for the special combinations and series of 
actions which are seen to follow. Such unions among nerve-centres 
appear to be formed when a period of cerebral inhibition, produced 
by a word of command, is seen to be followed by a co-ordinated series 
of, acts. A graphic tracing indicating suspension of microkinesis to 
the stimulus of sight and sound is given. It is further suggested that 
the brain action corresponding to thought, is the formation of func­
tional unions among cells, whose outcome is seen in the movements 
which express the thought, or its physical representation. Properties 
similar to those described in brain centres may be illustrated in 
modes of growth. Intelligence is then not a property of the brain, 
per se, but for its manifestation certain modes of brain action are 
necessary. In the special postures and movements described, a 
number of physical signs of brain states are offered to the clinical 
observer.

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