ABLATION OF THE CEREBELLUM. 



897 



the eyes. The performance of every movement quickly produces 

 great fatigue. Sight, hearing, and cutaneous sensation seem normal. 

 Gradual improvement succeeds in effacing more or less completely 

 the worse degrees of the above disturbances ; they persist obviously in 

 running longer than walking ; an unwonted movement is apt to pro- 

 duce them again, after they have disappeared from the more ordinary 

 movements ; thus the dog in shaking itself after a swim is apt to 

 shake itself off its balance, falling to the right. It is especially long 

 before the dog recovers his habitual bark. Entire disappearance of the 

 symptoms has not been obtained. Some glycosuria is usual in the 

 early stage, and the animal is for a long time thin, voracious, and 

 depressed ; perhaps 

 the longest of all 

 symptoms to persist 

 is tremor, when a 

 strongly- willed 

 movement is exe- 

 cuted. Cerebellar 

 tremor is one of the 

 most exquisite ex- 

 amples of " intention 

 tremor," i.e. of tre- 

 mor marking move- 

 ment that is "willed." 

 Ablation of the 

 whole cerebellum. 

 — The disturbance 

 ensuing immediately 

 upon ablation of the 

 whole cerebellum 

 appears at first 

 sight less severe than 

 that following re- 

 moval of a lateral 

 half of it. Opistho- 

 tonos, retraction of 

 the neck, throwing 

 up of the chin, tonic 

 extension and abduc- 

 tion of the limbs, 

 especially of the 

 fore-limbs, are 

 simply the bilateral duplication of the former picture, the asymmetrical 

 distortion of which is reduced to symmetry by doubling the insult. 

 The progress toward recovery is, as might be expected, more slow than 

 after unilateral ablation. Every attempt to move induces tremor and 

 oscillation, and long remains abortive. Swimming is much easier to 

 these animals than is walking (Luciani). 1 " I kept for eight months 

 a water-dog from which I had removed the cerebellum ; he made 

 hardly any progressive movement during all that time except when I 

 placed him in water " (Magendie). 2 The muscular power of the body is 

 weakened in all regions (Luciani), most notably in the hind-limbs and 

 1 Loc. cit. - " Physiologie," Paris, 1817. 



VOL. II. — 57 



Fig. 365. — Footprints of a dog ten days after ablation of the 

 middle lobe of the cerebellum. — Luciani. 



