460 PHYSIOLOGY CHAP. 



viz. examination of the tendon reflex, so that the essential basis 

 of his atonia is wanting." To this argument we replied to Ferrier 

 in 1895 : " No one has ever demonstrated that the tone of the 

 muscles bears any relation to the reflexes that can be evoked by 

 mechanical stimulation of their tendons. I fail to see why a 

 certain degree of atony should diminish or remove the tendon 

 reflex ; it even seems to me that it may exaggerate this reflex if 

 not in force certainly in its range. It is a fact that exaggeration 

 of the knee-jerk or patellar reflex is commonly noted by physicians 

 in cases with cerebellar lesions, apart from the contracture of the 

 paralysed limb. Since Terrier stated that after removal of the cere- 

 bellum the patellar reflex in his monkeys was grossly exaggerated 

 after a few months, he was logically bound to conclude either that 

 the tendon reflexes are in no way related to the muscular tone, or 

 that the absence of the cerebellum, far from producing atonia as I 

 maintain, induces, on the contrary, hypertonia or exaggeration of 

 muscular tone." 



Terrier, and later v. Monakow, did not dispute the facts on 

 which we founded the theory of astasia. He agreed with us that 

 the lack of stability or firmness in the limb, both in different 

 positions and in movement, is seen particularly on the side of the 

 lesion ; that it is not confined to the muscles of the trunk and 

 limbs, but extends to all the muscles ; and lastly, that it is 

 expressed in tremor, unsteadiness, and also in dysmetria of the 

 movements of the limbs, despite the functional compensation of 

 which the voluntary motor centres are capable. 1 



In conclusion, it follows that in the simplest and most typical 

 cases the clinical symptoms of diseases of the cerebellum in no 

 way contradict the experimental observations. When the 

 principal atonic, asthenic, and astatic symptoms of cerebellar 

 deficiency are absent or indefinite, it should be remembered that 

 the partial deficiency of the organ may be more or less perfectly 

 adjusted by a process of organic compensation. In cases in 

 which the cerebellar disease runs an acute course, and is accom- 

 panied by vertigo and irritative phenomena, these naturally pre- 

 dominate, and may disturb the co-ordination of movements so 

 much as to render the erect posture and locomotion impossible. 



1 Mingazzini lias unhappily replaced the term astasia by that which seems to 

 him more correct of dystasia or dysbasia, by which he means the difficulty which 

 cerebellar patients find in standing. He has evidently not grasped that the astasia, 

 or want of stability refers to all voluntary muscles and not merely to the muscles 

 of the lower limbs, neck and back, which are specially concerned in the erect 

 posture and in locomotion. 



This change in nomenclature, trifling as it seems, may well be a source of 

 ambiguity, obscurity, and confusion in the physiology of the cerebellum ! 



Less mischievous, but equally useless, is the substitution for atonia and asthenia 

 of hypotonia and hyposthenia which some clinicians think more appropriate, as 

 though it were not obvious that the lack of tone and energy in the muscles must 

 be understood in a relative sense, just as anaemia signifies not complete deficiency 

 but comparative poverty of amount of blood circulating. 



