380 
NATORE 
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[August 20, 1885 
still left him when awake quite conscious and able to understand, 
&c., using his remaining eye and ear for social intercourse. 
Now when these were carefully closed he became unconscious 
immediately, in fact slept, andslept until he was aroused again, 
or awoke naturally as we say after some hours. 
Hence the higher functions of the brain exercised when that 
organ is energising the reasoning of the mind, are absolutely 
dependent upon the reception of energy from the sense percep- 
tive areas. 
But my only point with reference to this part of the brain is 
to attempt to determine how far they are connected with the 
motor centres in the performance of a voluntary act. With the 
mechanism of choice and deliberate action I have nothing to do, 
but there can be no doubt that the part of the brain concerned in 
that process of the mind is directly connected with the motor 
region, as indicated on this diagram, to which I would now return. 
From what I have here written you read, arranged schematically, 
the psychical processes which for the sake of argument we may 
assume are carried on by the mind in these portions of the 
cortex. 
I wish to point out that we have structurally and physiologi- 
cally demonstrated with great probability the paths and centres 
of these psychical actions. There is no break: the mere sight 
of an object causes a stream of energy to travel through our 
semse areas, expanding as it goes by following the widening 
sensory paths here represented, and at the same time we feel 
our intellect learns that new ideas are rising up and finally 
expand into the process of deliberate thought, concerning which 
all we know is from that treacherous support, namely introspec- 
tion. 
Then comes impulses to action, and these follow a converse 
path to the receptive one just described ; the nerve energy is 
concentrated more and more until it culminates in the discharge 
of the motor corpuscles. We might represent the whole process 
of the voluntary act by two fans side by side, and the illimitable 
space above their arcs would serve very well to signify the dark- 
ness in which we sit concerning the process of intellectual 
thought. 
What I have hastily sketched is the outline of the process of 
an attentive or voluntary act. I say attentive advisedly, for I 
wish now to put forward the view that the proper criterion of 
the voluntary nature of an act is not the mere effort that is 
required to perform it, but is the degree to which the attention is 
involved. The popular view of the volitional character of an 
act being decided by the effort to keep the action sustained is 
surely incomplete, for in the first place we are not seeking to 
explain our consciousness of an effort. we endeavour to discover 
the causation of the effort. Our sense of effort only comes 
when the will has acted, and that same sense is no doubt largely 
due to the information which the struggling muscle sends to the 
brain, and possibly is a conscious appreciation of how much 
energy this motor corpuscle is giving out. 
Now to give you an example. Isee this tambour, and decide 
to squeeze it, and do so. Now this was a distinctly voluntary 
act; but the volitionary part of it was not the effort made, it 
was the deliberate decision to cause the movement. 
I may now point out that in this whole process we say, and 
say rightly, that our attention is involved so long as we are 
deliberating over the object, that as soon as another object is 
brought to us our attention is distracted, that is to say, turned 
aside. 
All writers are agreed that the attention cannot be divided, 
that we really only attend to one thing at once. 
It seems to me that this is so obvious as not to require experi- 
mental demonstration, but I have led up to this point because I 
now wish to refer to the third part of my subject, namely, 
the question as to whether we have a really double nervous 
system or not ; but by way of preface let me repeat that although 
we may have a subconsciousness of objects and acts, that that 
subconscious state is true automatism, and that such automatic 
acts are in no sense voluntary until the attention has been con 
centrated upon them. For example, again I press this tambour 
because I desire to raise the flag, and I keep that raised while I 
attend to what Iam sayingto you. My action of keeping the 
flag raised is only present to my consciousness in a slight or 
subordinate degree, and does not require my attention, deliberate 
thought or choice, and therefore, I repeat, is not a voluntary 
action, in fact it could be carried on perfectly well by this lower 
sensori motor centre, which only now and then sends up a 
message to say it is doing its duty, in the same way as a sentry 
calls out ‘* All well”’ at intervals. 
But to return, In consequence of the obvious fact that we 
have two nerve organs, each more or less complete, some writers 
have imagined that we have two minds; and to the Rev. Mr. 
Barlow, a former secretary of this Institution, is due the credit 
of recognising the circumstances which seem to favour that view. 
It was keenly taken up, and the furore culminated in a German 
writer (whose name I am ashamed to say has escaped me) 
postulating that we possess two souls. 
Now the evidence upon which this notion rests, that the two 
halves of the brain might occasionally work independently of 
one another at the same moment, was of two kinds. In the 
first place it was asserted that we could do two different things 
at once, and in the second place evidence was produced of people 
acting and thinking as if they had two minds. 
Now, while of course admitting that habitually one motor 
centre usually acts at one moment by itself, I am prepared to 
deny 2 ¢ofo that two voluntary acts can be performed at the 
same time, and I have already shown what is necessary for the 
fulfilment of all the conditions of volition, and that these con- 
ditions are summed up in the word attention. 
Further, I have already shown that when an idea comes into 
the mind owing to some object catching the eye, that both 
sensory areas are engaged in considering it. It seems to me I 
might stop here, and say that here was an @ gviord reason why 
two simultaneous voluntary acts are impossible ; but as my state- 
ments have met with some opposition, I prefer to demonstrate 
the fact by some experiments. 
The problem, stated in physiological terms, is as follows :— 
Can this right motor region act in the process of volition, while 
at the same time this other motor area is also engaged in a 
different act of volition ? 
Some say this is possible ; but in all cases quoted I have found 
that subconscious or automatic actions are confused with truly 
yoluntary acts. I mean that such automatic acts as playing bass 
and treble are not instances of pure volition, as the attention is 
not engaged on both notes at once. 
Consider for a moment the passage of the nerve impulses 
through the brain that would have to occur. At the outset we 
find that the sensory perceptive centres would have to be 
engaged with two different ideas at once ; but Lewes showed 
long ago that introspection tells us this is impossible, that ‘‘ con- 
sciousness is a seriated change of feelings,” he might equally well 
have said ideas. And again, we know that when two streams of 
energy of like character meet one another, they mutually 
arrest each other’s progress by reason of interfering with the 
vibration waves. 
I will show directly that this is actually the case in the action 
of the cortex when the above-mentioned dilemma is presented 
to it. 
The experiment I have devised for this purpose is extremely 
simple. 
A person who is more or less ambidextrous, and who has been 
accustomed for a long time to draw with both hands, attempts 
to describe on a flat surface a triangle and circle at the same 
moment. I chose these figures, after numerous trials, as being 
the most opposite, seeing that in a triangle there are only three 
changes of movement, while in a circle the movement is chang- 
ing direction every moment. To ensure the attempt to draw 
these figures simultaneously succeeding, it is absolutely necessary 
that the experimenter should be started by a signal. ' 
When the effort is made there is a very definite sensation in 
the mind of the conflict that is going on in the cortex of the 
brain. The idea of the circle alternates with that of the tri- 
angle, and the result of this confusion in the intellectual and 
sensorial portions of the brain is that both motor areas, though 
remembering, as it were, the determination of the experimenter 
to draw distinct figures, produce a like confused effect, namely, 
a circular triangle and a triangular circle. If the drawing is 
commenced immediately at the sound of the signal it will be 
found that the triangle predominates ; thus, if I determine to 
draw a triangle with my left hand and a circle with my right, 
the triangle (though with all its angles rounded off) will be fairly 
drawn, while the circle will be relatively more altered, of course 
made triangular. On the other hand, if the two figures are not 
commenced simultaneously. it will be found that usually the one 
begun last will appear most distinct in the fused result, in fact 
will very markedly predominate. 
Now the course of events in such an experiment appears to 
be clear. 
The idea of a triangle and circle having been presented to 
the intellect by the sensory centres, the voluntary effort to 
