290 
Proceedings of the Royal Society of Edinburgh. [Sess. 
In the middle (fig. 5) and lowermost regions of the pons these smaller 
bundles on the lateral, ventro-lateral, and mesial aspects gradually dis- 
appear, and the degeneration becomes more uniformly scattered throughout 
the central and larger bundles, which at the lowest levels are reunited into 
a single fasciculus just before it passes into the medulla oblongata to form 
the anterior pyramid. 
Fig. 5. — Transverse section through 
middle of pons varolii. 
Throughout the pons, in all its levels, there is a very copious fine 
degeneration amongst the nerve cells of the nuclei pontis on all aspects 
of the pyramidal bundles. This fine degeneration is strictly confined to 
the side of the lesion, and does not extend beyond the median raphe. No 
degeneration is to be found in the fillet, and no fibres can be traced to 
any of the motor nuclei either in the pons or mesencephalon. 
In the highest levels of the medulla oblongata the transverse section 
Fig. 6. — Transverse section through upper 
part of medulla oblongata. 
of the anterior pyramid is oval in shape, being flattened antero-posteriorly,. 
but slightly below this, where the plane of the section passes through the 
upper extremity of the inferior olivary nucleus, it is roughly triangular, 
and from the sharp postero-mesial angle a few fibres can be seen to come' 
off (fig. 6) ; they are directed backwards and inwards, and after crossing in 
the ventral part of the median raphe they are lost in the formatio reticularis 
of the opposite side. These continue to come off, not in bundles, but as. 
single fibres, and to take the course described, throughout the whole upper; 
