Bauhaus-Universität Weimar

624 
THE CEREBELLUM. 
lesion does not abolish the motion of the iris,—on the contrary, that 
these motions sometimes continue; 3. that by removing a larger portion 
of the optic lobe, or completely extirpating it, vision, as well as the con¬ 
tractile power of the iris, is completely destroyed; 4. that mutilation of 
the optic lobe has nearly the same effect on the eye as injury to the 
optic nerve; 5. that the muscular weakness of the opposite side of the 
body, produced by the mutilation of one optic lobe, is only temporary; 
6. that the infliction of this injury on one side of the body, causes the 
animal to move round on its axis, as if giddy; 7. that no other effect 
than those mentioned follow the mutilation of the corpora quadri- 
gemina,—thus, for example, that no disturbance of memory or con¬ 
sciousness is produced. 
The only point in which the observations of this experimenter differ 
from those of M. Flourens, has reference to the convulsions produced 
by injury to the optic lobes, which, in M. Hertwig’s experiments, never 
ensued. The opposite result obtained by M. Flourens was perhaps due 
to his incision being carried too deeply. 
V. Of the Cerebellum. 
The functions of the cerebellum have been made the subject of in¬ 
teresting experiments by Rolando, Flourens, Magendie, Schoeps, and 
Hertwig. 
M. Rolando constantly observed that the diminution of the move¬ 
ments was in a direct ratio with the lesion of the cerebellum; that stupor 
was never produced, nor the sensibility of any part of the body im¬ 
paired; but that the power of the muscular movements was lost. The 
animals kept their eyes open, and regarded surrounding objects, but in 
vain endeavoured to execute any of the movement necessary for loco¬ 
motion. An animal in which one side of the cerebellum had been re¬ 
moved, fell upon the same side, not being able to support itself upon the 
leg of that side. These results induced Rolando to adopt a supposition 
quite incapable of proof, namely, that the cerebellum is the organ 
destined for the generation of the nervous principle, which he compared 
with electricity; and that the alternate layers of white and grey sub¬ 
stance of the cerebellum act, as Reil also imagined, in the way of a 
galvanic pile. 
The experiments of M. Flourens (Loc. citât, pp. 18 and 36,) are 
more lucid and more decisive in their results. He found that the ani¬ 
mals evinced no signs of sensibility in the cerebellum while it was being 
removed. He extirpated the cerebellum in birds by successive layers; 
feebleness and want of harmony of the movements were the conse¬ 
quence. When he had reached the middle layers, the animals became 
restless without being convulsed; their movements were violent and 
irregular, but their sight and hearing were perfect. By the time that 
the last portion of the organ was cut away, the animals had entirely 
lost the powers of springing, flying, walking, standing, and preserving 
their equilibrium. When an animal in this state was laid upon the 
back, it could not recover its former posture; but it fluttered its wings, 
and did not lie in a state of stupor; it saw the blow which threatened 
it, and endeavoured to avoid it. Volition, sensation, and memory,
        

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