viii THE HIND-BEAIN 469 



ments are lacking in decerebellated animals ; in a word, asthenia 

 is for him a result of disturbance of the co-ordination of the 

 movements. 



As evidence for this loss of co-ordination Lewandowsky 

 adduces the phenomenon which we described minutely under 

 the name of dysmetria, as expressed in the so-called hen's gait. 

 Lewandowsky regards this symptom, which can also be seen after 

 section of the dorsal spinal roots and in tabes dorsalis, as all- 

 important. Asthenia, atonia, ataxia, fall into the second place ; 

 they are not fundamental phenomena of cerebellar ataxy, but 

 are merely secondary to dysmetria and to the imperfect co- 

 ordination of the voluntary movements, which in its turn is due 

 to disturbance of the muscular sense ! 



" Luciani," he adds, " has not been able to clear up the 

 symptoms in cerebellar ataxy, because he overlooks one effect of 

 cerebellar lesions which we should place in the first rank 

 alterations of the muscular sense. While Luciani, after thousands 

 of experiments, has never observed disturbances of the muscle 

 sense, we, on the contrary, say that every motor trouble due to 

 cerebellar lesions is accompanied by it." 



This view, which is denied by most authoritative observers, 

 compels Lewandowsky to admit : 



(a) That the cerebellum is not the only central organ of 

 muscular sense, as the cerebral cortex also participates ; 



(6) That it does not represent an intermediate station on the 

 paths of muscular sensibility running to the brain, but that there 

 are direct paths between the cerebrum and the spinal cord, which 

 are unconnected with the cerebellum ; 



(c) That there is both conscious and subconscious regulation of 

 movement by the muscular sense ; that the cerebrum attends to 

 conscious regulation, while the cerebellum has no other task 

 than that of controlling and directing the subconscious move- 

 ments ! 



But these conclusions invalidate all his previous statements : 

 if the cerebellum is not the seat of conscious sensations, cerebellar 

 ataxy obviously cannot be a sensory ataxy like that which is 

 seen after section of the roots and in tabes, nor is the cerebellum 

 a ' centre for the muscle sense. If the spino-cerebral sensory 

 paths are unconnected with the afferent spino-cerebellar paths, it 

 is clear that decerebellated animals cannot exhibit disturbance of 

 the muscle sense, since the spino-cerebral paths that transmit 

 the impressions of the state of the muscles to the cerebral 

 centre are intact ; it is accordingly absurd to assume that the 

 decerebellated animal does not perceive and correct abnormal 

 positions of its limbs, if it be once admitted that the cerebellum 

 is not the seat of conscious sensations. 



It must be admitted that dysmetria of movement can be 



