EXTIRPATION OF THE CEREBELLUM. 725 



all other similar operations, we must distinguish sharply the phenomena manifested during re- 

 cove^ from those after complete recovery. During the first period of six weeks, from the time 

 of the operation until complete recovery, the symptoms are those of injury and irritation of the 

 divided peduncles, along with those resulting from the removal of the organ. They are clonic 

 contractions of the muscles of the fore limb, neck, and back, passing into tonic contractions 

 when the animal attempts to move, and also weakness of the hind legs, so that all the normal 

 voluntary movements are interfered with, i.e., inco-ordinated, although these symptoms may 

 be explained by the injury to adjoining parts. There was no sensory disturbance or loss of the 

 muscular sense, although closing the eyes rendered standing impossible. As recovery takes 

 place, these symptoms disappear, and the animal enters on the second period, where the 

 symptoms depending on the actual loss of the organ are pronounced. The contracture and 

 pseudo-paralytic weakness disappear, while there are alterations in the tone of the individual 

 muscles, producing a sort of "cerebellar ataxy." The dog could swim in quite a normal 

 manner, its power of equilibration was not interfered with, but acts requiring a greater develop- 

 ment of muscular energy could not be properly executed. This period lasted four to five months. 

 After this time its health gave way, there was otitis, conjunctivitis, articular and cutaneous 

 inflammations, while a peculiar form of marasmus set in, the animal dying after eight months. 

 In fishes also, the removal of the cerebellum does not affect their power of locomotion 

 (Bandelot). ] 



Duration of the Phenomena. After superficial lesions, or after a deep incision, 

 the disturbances of co-ordination soon pass away (Flourens). If the injury affects 

 the lowest third of the cerebellum, the motor disturbances remain permanently. 

 Symmetrical lesions do not disturb co-ordination (Schiff). After removing the 

 greater portion of the cerebellum in birds, AVeir-Mitchell has observed that the 

 original disturbances gradually disappear ; and after months only slight weakness 

 and a condition of rapid fatigue remain. 



After ablation of the cerebellum, secondary degeneration occurs in the part of the pons 

 around the pyramids, the lower olives, all the cerebellar peduncles and the direct cerebellar 

 tract, usually on the same side (Flechsig). It is found also in individual fibres in all the 

 cranial nerves and the anterior roots of the spinal nerves (3farchi). 



In the dog, superficial injuries of the vermiform process, or of one-half of the organ, produce 

 merely temporary disturbances ; while deep injuries to the vermiform process, or removal of one 

 hemisphere and a part of the vermiform process, cause permanent rigidity of the legs and shaking 

 of the head ; if the worm and both halves are destroyed, there follows permanent pronounced 

 disturbance of co-ordination (v. Mering). According to Baginsky, destruction of a large part 

 of the vermiform process alone causes in mammals permanent disturbance of co-ordination. 

 Terrier found that a vertical section of the cerebellum in monkeys, produced only inconsiderable 

 disturbances of equilibrium ; after injury of the anterior part of the middle lobe, the animal 

 often tumbles forward; while, when the posterior part is injured, it falls backward. After 

 injury of the lateral lobe, the animal is drawn towards the affected side {Schiff, Vulpian, 

 Ferrier, Hitzig). If the middle commissure be injured, the animal rolls violently on its long 

 axis towards the injured side (Magendie). Paralysis never occurs after injuries of the cerebellum, 

 nor is there ever disturbance of sensation or of the sense of touch. Luciani found that, in 

 animals with the cerebellum extirpated, marasmus ultimately set in. In frogs, an important 

 organ concerned with motion lies at the junction of the oblongata with the cerebellum (Eckhard). 

 After it is removed the animal can no longer execute co-ordinated jumping movements, nor can 

 it crawl (Goltz). 



[In man, the cerebellum is connected with the maintenance of the equilibrium. There may 

 be a lesion of the hemispheres without any marked symptoms ; but if the middle lobe be injured 

 or pressed on by a tumour, there is usually a reeling or staggering gait, like that of a drunken 

 man. Ross points out that, if the tumour affect the upper part of this lobe, the tendency is to 

 fall backwards, and if in the lower part, to fall forwards or to revolve round a horizontal axis. 

 Vomiting is frequently persistent and well marked, while there may be nystagmus and tonic 

 retraction of the head.] 



After injuries of the cerebellum, involuntary oscillations of the eyeballs or nystagmus, as 

 well as squinting (Magendie, Jlertwig), have been observed ; while Ferrier observed movements 

 of the eyeballs after electrical stimulation. According to Curschmann, Eckhard, and Schwann, 

 this occurs only when the medulla oblongata is involved ( 379). 



Effects of Electricity and Vertigo. If an electrical current be passed through the head, by 

 placing the electrodes in the mastoid fossae behind both ears, with the + pole behind the right 

 and the - pole behind the left ear, then on closing the current, there is severe vertigo, and the 

 head and body lean to the + pole, while the objects around seem to be displaced to the left. 

 If the eyes be closed, while the current is passing, the movements appear to be transferred to 

 the person himself, so that he has a feeling of rotation to the left (Purkinje). At the moment 



