viii THE HIND-BRAIN 459 



bed. In this position of stable equilibrium they are capable of 

 carrying out any movement rapidly and completely. It is rare to 

 find that one or the other leg, if raised, trembles slightly or 

 makes shaky or disconnected movements. "When the patient 

 lies on his back in bed," writes Nothnagel, " the leg-movements 

 are made quickly and certainly ; the subject has a clear idea of 

 their position and manages to place one limb actively in exactly 

 the same place to which the other has been brought passively." 



This, which agrees perfectly with experimental observations, 

 proves that cerebellar patients like decerebellated animals retain 

 on the one hand the complete ability to co-ordinate their move- 

 ments, on the other the integrity of the muscular sense, that is, 

 full consciousness of the position of the limbs in space, both during 

 rest and in muscular activity. 



It is curious to note that while v. Monakow expressly admits 

 that " the phenomena of cerebellar ataxy in man coincide in 

 essentials with the observations made upon animals," he expressly 

 denies that asthenia and atonia are essential factors in clinical 

 cerebellar ataxy. 



But it is only necessary to glance through the cases collected 

 by Adler (1899), the majority of which were tumours in one or other 

 part of the cerebellum, to see that asthenia, expressed in the words 

 " weakness " or " paresis " of the muscles of the legs, was expressly 

 noted in a great number of cases. The most striking are 11 cases 

 of tumour of one cerebellar hemisphere in which muscular weak- 

 ness, or even a distinct hemiparesis, was noted definitely in the 

 homolateral side. In 6 other cases where there is no reference 

 to the strength of the limbs it is stated that the gait was unsteady 

 and uncertain, and that the patient had a tendency to fall, or did 

 fall, towards the side in which the tumour lay. In 8 cases, lastly, 

 it was noted that the patient was unable to stand or walk, owing 

 merely to irritative phenomena and vertigo. 



In denying the occurrence of atonia v. Monakow repeated 

 Ferrier's objection that the tendon-phenomenon or knee-jerk was 

 exaggerated, according to Eisien Russell, in animals after opera- 

 tions on the cerebellum. He admits that Gowers, Jackson, and 

 Dercum, on the strength of clinical observations, ascribed a marked 

 influence on muscular tone to the cerebellum. " But," he adds, 

 " if observations on the absence of patellar reflex where there are 

 circumscribed lesions of the cerebellum are not wanting, in other 

 cases of cerebellar tumour the tendon reflexes are normal. It is 

 certain that depression of muscular tone involving loss of the 

 patellar reflex is very inconstant in cerebellar affections in man. 

 Luciani assumes that the alteration in tone is so delicate that 

 clinicians do not succeed in detecting it. He himself, however 

 (as Terrier justly points out), has neglected the very method which 

 physicians adopt in every case for testing the tone of the muscles, 



