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fined to the arm area, but in the one case some fibres terminate in the 
cervical enlargement, and in the other a few certainly do pass to the 
lower end of the cord. Melius denied Sherrington’s statement ; he could 
trace no fibres beyond the upper dorsal region following his localised 
extirpations in the arm area, but his lesions were made in the post-central con- 
volution behind the fissure of Rolando, and so outside the true motor area. 
Two possible explanations suggest themselves for the presence of these 
fibres in the spinal cord, and for those stray fibres which invade the 
fronto-pontine and temporo-pontine bundles in the internal capsule, crusta, 
and pons. They may be due to unavoidable injury to the cortex of the 
brain beyond the motor area during the operation, through interference with 
the blood supply, or mechanically by pressure, by which a few of the cells 
are damaged to such an extent as to lead to degeneration of the fibres 
which take origin in them. Thus, after extirpation of a portion of the 
arm area, some degenerated fibres may come from damaged cells in the leg 
and face areas, and even from the cortex outside the true Rolandic area. 
On the other hand, the areas for leg, arm, and face may not be so 
strictly limited as stimulation with minimal currents by the unipolar 
method would indicate, and a few fibres destined for the innervation of 
the leg muscles may take origin from cells situated within the arm area, 
and vice versa. 
With regard to the degeneration following total extirpation of the 
motor cortex, we corroborate the results stated in a former paper * by one 
of us, and are in agreement on most points with others who have used this 
method. In all our larger lesions the fine degeneration in the nuclei pontis 
is very evident, indicating an important connection between the pyramidal 
fibres and the grey matter in this region. 
We have not been able to make out the accessory fillet of von Bechterew, 
described by him, and by Hoche,f Schlesinger,j Barnes § and others, in the 
human subject. This is a bundle of fibres which leaves the pyramidal tract 
in the mesencephalon, and running outwards and backwards through the 
substantia nigra, passes into the outer part of the mesial fillet in the upper 
levels of the pons. A similar bundle of descending fibres (Spitzka’s bundle) 
in the fillet, nearer the middle line, has been named the mesial accessory 
fillet. These two bundles were believed by Hoche to end in certain of the 
cranial motor nuclei. In many of our cases numerous fibres leave the 
pyramidal tract in the crusta, and do pass in the direction described by 
* Simpson, Internat. Monatschr. f. Anat. u. Physiol ., Bd. xix. (1902), p. 1. 
t Hoche, Arch. f. Psychiat. u. Nervenkr., Bd. xxx. (1898), p. 103. 
£ Schlesinger, Neur. Gent., 1896, p. 146. § Barnes, loc. cit. 
