vin THE HIND-BKAIN 477 



(tZ) An unpaired centre for the muscles of the back, in the 

 lowest part of the lobulus medianus posterior. 



These results approximate closely to Bolk's diagram of localisa- 

 tion ; but the inadequacy of Pagano's method for any exact 

 determination of the cerebellar centres may be concluded both 

 from the inconstancy and the variability of the reactions excited 

 by the curare at the different points of injection, and from his 

 own observation that a deep injection of curare into the lobus 

 anterior causes violent excitation of almost all cerebral centres, 

 with varied sensory and motor manifestations termed by Pagano 

 psychic strychnmism or motor delirium, which rapidly caused the 

 death of the animal. 



These studies of the effect of poisons, applied to the cerebellum, 

 were continued in our laboratory by Magnini under Baglioni's 

 guidance (1910). Baglioni's previous work had proved that local 

 application of weak solutions of carbolic acid affect electively 

 the motor elements of the spinal cord, and solutions of strychnine 

 the sensory elements of the whole nervous system (p. 264 et seq.*). 

 It was therefore hoped that by employing these two poisons as 

 chemical stimuli of the cortex and deep parts of the cerebellum, 

 it might be possible to obtain facts of importance for the theory 

 of cerebellar localisation. 



But the results were disappointing, though they brought into 

 prominence symptoms which demonstrated the specifically different 

 nature from the corresponding elements of the cerebrospinal axis 

 of the afferent and efferent elements of the cerebellum. 



Carbolic acid, applied to the crus primum and secundum of 

 the cerebellum, in any strength of solution (1*3-6 per cent on 

 discs of filter paper) has no immediate effect. This means that 

 the cerebellar cortex, so far as we know, either contains no motor 

 elements, or these are specifically different in character from the 

 spinal motor elements. 



Strychnine, when applied to the lobulus medianus posterior, 

 lobulus paramedianus, or crus secundum, either to the surface or by 

 injection, produces no special symptoms, according to the various 

 regions excited, but only more or less general movements of the 

 head, neck, trunk, and limbs of the side homolateral with the 

 stimulation. Application by discs of filter paper either produces 

 no effect or mere twitches of the facial muscles. Superficial 

 injections merely lead to raising of the fore -leg on the same 

 side, blepharospasm, salivation with rhythmical movements of the 

 jaw, tonic contraction of the two limbs on the homolateral side, 

 with tactile hyperaesthesia of the skin of the homolateral side of 

 the face. 



These results, while they do not disprove the concept of 

 localisation in the cerebellum, give no decisive argument in favour 

 of it. The amount of strychnine used to evoke these phenomena 



