RECENT NEUROLOGICAL PROGRESS. 279 



dog the prehensile precision of the neck is especially 

 exercised in feeding from the dish on the cage floor, 

 and it was then that oscillation of the head and neck 

 became especially violent. Ablation of the limb region 

 of the opposite cerebral hemisphere did not reduce but 

 rather aa-oravated the tremor, as also the asthenia of the 

 muscles. 



Luciani notes as an important distinction between the 

 disturbance due to ablation of the limb region of the cerebral 

 cortex and that due to ablation of the cerebellum, that in the 

 former there is great defect of tactile and muscular sensation 

 of the limb, in the latter these are not obviously interfered 

 with. " Basta toccare leggermente, in qualsiasi punto della 

 cute, l'animale operato al cervelletto, mentre e intento a 

 cibarsi, oppure mentre ha gli occhi bendati, perche esso, 

 con qualche movimento reattivo, mostri subito di aver 

 avvertito il contatto. Basta collocare in posizione 

 incongrua l'uno o l'altro arto dell' animale, perche 

 subito esso reagisca riponendo l'arto nella posa nor- 

 male. In questo gli animali scerebellati si comportano in 

 maniera affatto opposta a quelli privati di una porzione 

 abbastanza cospicua delle sfere sensorio-motrici della cor- 

 teccia cerebrale." 



Yet the large command of motility residual in absence 

 of even the whole cerebellum, and of the "sfere sensorio- 

 motrici " of both cerebral hemispheres, is very evident in the 

 history of a dog observed for a period of twelve months 

 following- on those ablations. The creature swam " a mera- 

 viglia," keeping its head up from the water in normal 

 fashion, directing its course to right or left or straight 

 forward at pleasure. Compensatory actions play a great 

 part in gradually minimising the effects of the disturbance. 

 Thus the insecurity of gait is minimised, as Luciani's 

 tracings demonstrate, by the limbs being more widely spread 

 and a wider base obtained for supporting the gravity of the 

 body. After the " irritation symptoms " due to still active 

 trauma have passed off, there is, Luciani believes, no real 

 restoration of the actions that disappeared, though more or 

 less compensation is obtained by means of other actions. 



