No. 388.] MAINTENANCE OF THE EQUILIBRIUM. 325 
at the same time he may not be able to send sufficient stimulus 
to his muscles to produce the contractions necessary for his 
purpose. This defect in the control of the muscular innerva- 
tion is called ataxia, and since it is dependent on a disease of 
the spinal cord it is known as spinal ataxia. 
This disease offers yet another phenomenon. During its 
first stages the patient is generally able to stand quite firmly, 
even though his feet be placed near together, thus reducing his 
stability as much as possible. But no sooner does he close his 
eyes than he begins to totter and become dizzy, finally falling, 
unless he is supported. The explanation of this phenomenon, 
known as Romberg’s symptom (static ataxia), is to be found in 
the fact that in closing the eyes the control of the equilibrium 
dependent on them, a very important factor, is lost. 
There is a particular kind of dizziness, called optical dizziness, 
which depends upon a derangement of the nerves of the eye 
muscles. Let us imagine that our eyes move without our being 
conscious of it. It will seem to us that the objects about us 
have changed their positions in relation to our body ; and since 
walls, trees, and pieces of furniture, which we know to be fixed, 
appear in a different direction, we conclude that our body has 
moved, This erroneous impression passes to the center of 
coordination, and is answered by a compensating movement of 
the body, which is naturally unsuitable; then we again feel a 
loss of balance. Thus is explained the uncertainty in standing 
and walking which is observed as resulting from many kinds of 
disturbances in the movement of the eye. 
That dizziness also arises from the digestive organs, by means 
of the visceral sensations, is a fact well known to the laity. 
But the process here taking place is in no way clear to us. 
The phenomena of dizziness and loss of balance, which have 
their origin in the ear labyrinth, the special organ of equilibra- 
tion, are of particular interest. Here also we must distinguish 
whether we have to do with false sensations which are trans- 
mitted from this sense organ to the brain, or whether this kind 
of sensations is entirely lacking. 
It is plain to see that the latter condition might easily be 
followed by less serious results than the former; for if the 
