fiO Researches into the Functions of the Cerebellum. [Jan. 25, 



directed up, and the spinal column is arched with its concavity to the 

 side of the lesion. 



3. Incoordination, chiefly in the limbs of the same side. 



4. Rigidity, most marked in the extremities of the side of the lesion, 

 and preponderating in the anterior extremity of the side. 



5. Exaggeration of the, tendon reflexes most marked on the same 

 side. 



6. Motor paresis affecting both extremities on the side of the 

 lesion, and the posterior extremity of the opposite side. 



7. Anaesthesia and analgesia having the same distribution as the 

 motor paresis. 



8. Deviation of the opposite eyeball downwards and outwards, 

 while that of the same side, if deviated, looks upwards and to the 

 side of the lesion. 



9. Lateral nystagmus, the jerks being from the opposite side to- 

 wards the side of the lesion. 



The phenomena which characterise ablation of different parts of 

 the middle lobe, and of the whole organ, are similarly described. In- 

 coordination is next discussed, and it is urged that, instead of looking 

 on the cerebellum as a distinct organ which has a special function, 

 distinct from those subserved by other parts of the central nervous 

 system, it would be more correct to look on it as a part of that 

 system, having many functions in common with other parts of it, the 

 chief difference between one part of this great system and another 

 being the degree in which different functions are represented in any 

 given part : e.g., with regard to motor power, the anterior extremity 

 is maximally represented in the cerebrum and minimally in the 

 cerebellum, whereas the trunk muscles are minimally represented in 

 the cerebrum and maximally in the cerebellum. Arguments are ad- 

 duced, in favour of looking on the ocular deviations which result 

 from ablation of parts of the cerebellum as paralytic rather than 

 irritative phenomena, and two forms of nystagmus are recognised, as 

 consequent on cerebellar lesions, one which is spontaneous, and the 

 other which is only evoked on voluntary movements of the globes, 

 and the probable difference in their aetiology discussed. Finally, 

 the phenomena characteristic of unilateral ablation of the cerebellum 

 are contrasted with those the result of extirpation of the labyrinth, 

 and it is shown that no single phenomenon is the same in the two. 



