foreground, when (he same niovemeiils are perfoi'iiied \vi(h eves shut, 

 or wlieii the}' are walking in the dark and cannot make nse of their eyes. 



Tliis help may be i-athei' sufficient in light cases of tabes, but it 

 will not be possible to totally improve the disturbance, if the illness 

 has become of a rather serious natui-e. if wo give to this kind of 

 patients contact-sensation by the arms, thei-e will yet be an impottant 

 improvement. (Fig. 2). 



Consequently from this follows as is moi-eover near at hand, that 

 the equilibrium sensation of (he arms, being of the same sort as of 

 the trunk and limbs, com[)ensates in reality, while the other senses 

 can only correct to a certain degi'ee. 



I have pointed out in the preceding [)ages, that one finds the same 

 facts back in lesions of the vestibular organ. Here too the ataxia 

 improves, when the patient uses his eyes (Fig. 3), l)ut here too 

 one finds, that idlieii the eyes Cdiinot safjicienthj correct (tiiij more, 

 the ataxia totally or nearly totally vanishes, when through the anus 

 equilibrium-sensation rs obtained with the surround iny loorld. Here 

 too we find, that the equilibrium sensation of the arms acts totally 

 or nearly totally compensatory. (Fig. 4). 



The question arises how we can explain this. 



I think that I may except as easy to comprehend, that the pro- 

 prio-ceptive stimuli of the equilibriifm sensation of the trunk and the 

 limbs and those of the vestibular oryan are to be considered of the 

 same sort. 



Referring to our equilibrium, no ditference should be made between 

 the afferent-proprioceptive stimuli, which from the vestibular organ 

 are conducted to the central nervous system and those which come 

 there from the trunk and the limbs. It is a large system of equili- 

 brium fibres that is spread over our whole body and its aim is to 

 regulate the equilibrium. 



The sixth sense, the one for our equilibrium, has therefore iu)( 

 only to be looked for iji (he vestibular organ, but it is, as I explained, 

 spread over the whole of our body. The vestibular organ is but apart of it. 



Now probably one might ask, why does tliat organ form a whole 

 while in (he o(her equilibrium padis very liltle independency is 

 found. The reason foi' this, according to my view, has (o be found 

 in the extraordinary relation of the head, in comparison to the 

 rest of the body. 



To make this clear, one has to keep in mind, that the equilibrium 

 sensation of the different parts of our body is not everywhere the 

 same, or otherwise expressed, is no tevoiy wheie ecpiivalent. F.g. 

 the equilibrium sensation for the tiunk, which can oidy jnove 



