364 Dr. F. H. Thiele. Efferent Relationship of Optic [Apr. 19, 
middle peduncle. These results occurred whether the pyramidal tracts were 
intact or degenerated. 
From these experiments it appears that the cerebellum by way of its 
peduncles exercises a control over the skeletal muscles, the control being 
chiefly over the muscles of the trunk and girdles. 
During the course of these experiments stimulation in the neighbouring 
regions of the lateral fillet, posterior corpus quadrigeminum, and [Vth nerve 
produced the following results :— 
Stimulation of the [Vth nerve produced movement of the homolateral eyes 
upwards and outwards. 
Stimulation of the lateral fillet produced pricking of and rotation of the 
opposite ear outwards and backwards, conjugate deviation of the eyes to the 
contralateral side. 
Stimulation of the lateral aspect of the posterior corpus quadrigeminum 
produced no result. Vocalisation was not noted, since the animal was 
aneesthetised through a tracheotomy tube. 
C. fesults obtained by Stimulation of the Cut Surface of the Optic Thalamus 
and Mesencephaton. 
It was only when the posterior part of the optic thalamus was stimulated 
that any results were obtained. 
Stimulation in this region of what appeared to be the median nucleus 
produced very definite motor phenomena. The animal presented a certain 
degree of decerebrate rigidity, stimulation produced retraction and flexion of 
the homolateral fore-limb, protraction and extension of the contralateral 
fore-limb. The homolateral hind-limb was in some cases extended, the 
contralateral flexed. In other cases the result was to produce a flexion of 
both hind-lhmbs. 
There was also usually contraction of the trunk muscles, most marked on 
the homolateral side, causing in some cases rotation, so that the homolateral 
shoulder became the lower. 
This result was obtained in cats and monkeys, and was quite independent 
of the pyramidal tracts, since it was always obtained in those cases where the 
pyramidal tracts had been eliminated by degeneration previously. Similar 
results were obtained when the cut surface of the mesencephalon was stimu- 
lated at different levels. The area from which these movements were 
obtained was smaller than that in the thalamus. The tract appeared to be 
the rubro-spinal tract or one coming down with it. The tract was traced as 
far as the medulla. 
The strength of faradic current required to produce these movements was 
