OF THE SPINAL CORD WITH THE CEREBELLUM. 
569 
ramidal bodies, are separated from the posterior fibres of the antero-lateral columns, 
already described as ascending - to the cerebellum, by fibres which occupy a place in 
the middle of the side of the cord. These fibres, which subsequently ascend through 
the pons Varolii to the cerebrum, and form the upper portion of the crus cerebri, have 
lately been described by Sir Charles Bell as a portion of the tract of sensation. The 
cerehellic fibres of the anterior columns, as they ascend to the cerebellum, pass princi- 
pally below the olivary bodies, sometimes crossing - the lower border of these bodies, 
while others which are deeper seated pass to the inner side of them. The whole, 
during their ascent to the cerebellum, cross to the outer side of the tract of sensation 
above referred to and sensory root of the fifth pair of nerves, and then, plunging - into 
the substance of the corpus restiforine, interlace with the true posterior columns of 
the cord, and finally terminate in the cerebellum. See fig. 2. 
These fibres, whose importance to the physiologist as proving unequivocally the 
existence of a complete communication between the motor tract of the spinal cord 
and the cerebellum need not be dwelt on, are most easily demonstrated in the follow- 
ing way : Let the posterior column be separated from the antero-lateral column, at 
the posterior lateral fissure, about two or three inches below the pons Varolii; and 
subsequently draw very carefully the posterior column, thus split from the anterior, 
up towards the cerebellum. The rent in the cord, which tears smoothly till it reaches 
the lower edge of the corpus restiforme, is there arrested by the cerebeUic fibres of the 
anterior columns, unless too much force has been used, in which case they are easily 
torn through, and escape observation. They may be likewise shown by making the 
rent in the antero-lateral column itself, exactly at the centre of the lateral face of the 
cord, thus dividing the cord into two halves, an anterior and a posterior, and then 
continuing the rent in the same way. Again, these fibres may be shown by tearing 
up that portion of the front of the cord which is anterior to the anterior roots of the 
spinal nerves, which portion will be found, at the point where the anterior columns 
decussate, to split into three sets of fibres : one set of fibres cross to the opposite 
side ; a second run to the inner side of the corpus olivare ; a third set, which are not 
numerous, run below and to the outer side of the corpus olivare, and, ascending to 
the cerebellum, constitute a portion of the fibres in question. 
If the sensory root of the fifth pair of nerves be traced through the pons Varolii, and 
the fibres which lie to the outer side of it in the medulla oblongata examined with 
care, they will be found connecting the anterior portion of the cord with the cerebel- 
lum ; or, in other words, they will be found to be the cerebeUic fibres of the anterior 
columns. The surface of these fibres is represented in fig. i. e. as exposed by simply 
raising the pia mater, and carefully scraping the surface in a portion of the medulla 
previously hardened by alcohol. The deeper-seated are represented divided just at 
the point where they cross the sensory root of the fifth pair of nerves, which nerve is 
thus exposed to view in fig. 2. e. Ahe corpus olivare having been raised from its natu- 
ral position. 
MDCCCXXXVI. 4 D 
