———_—_—— SS Oh COCO OO 
MULTIPLE NEUROMATA OF THE CENTRAL NERVOUS SYSTEM. 757 
In consequence of the existence of this Ablassungzone the intra-medullary part 
of some anterior nerve roots is divided into a central and peripheral part. The root 
bundles outside the pia are cut transversely, so that the emerging roots would seem to 
take very rapidly a course in the longitudinal direction of the cord. The anterior nerve 
bundles have thus a central part, an Ablassungzone, and a peripheral part. By the 
varying position of the Ablasswngzone the length of these portions of the nerve is 
altered. If it lies within the glia border layer, then the peripheral part is lengthened, 
and if it lies in the pia the peripheral part is very short. 
In Weigert-stained preparations, amongst the thick root fibres—those immediately 
peripheral to the Ablassungzone—small bundles of fine fibres could be traced, either 
free or disposed around the vessels. The anterior root artery, cut transversely im- 
mediately lateral to the nerve root, was almost invariably in the lumbar cord surrounded 
by a reticulum of fine fibres (fig. 13). A passage of fibres from anterior roots to this 
vessel could never be traced, for an anterior root bundle seemed to divide and enclose 
the vessel. In other preparations the Ablassungzone of one bundle was unrecognis- 
able and its place was taken by a fibrosis, within which could be traced an interlacing 
of fibres which were finer than the intra-medullary fibres with which they appeared to 
be continuous. From this interlacing, in which fibres were cut transversely and longi- 
tudinally, there seemed to be a definite gathering up of fine fibres to pass into the pia. 
A very clear picture of such a group of fibres passing laterally is seen in fig. 39. A 
careful comparison of numerous such pictures made it not unreasonable to assume that 
here the Ablassungzone had been intra-medullary, and that from the point immediately 
peripheral to it the pial fibres had arisen, the secondary fibrosis involving the intra- 
medullary course of the fibres. 
The direct association of the abnormal pial fibres with the anterior nerve bundles 
immediately peripheral to the Ablassungzone seemed to be confirmed by further 
study of the preparations. The connections were often very few, but they must often 
have been removed by the increasing fibrosis. 
It must further be noted that the fibres of several nodules, situated midway 
between the grey matter and the periphery of the cord, seemed as if they unwound 
into strands directly continuous both centrally and peripherally with anterior root 
bundles. A careful examination, however, of serial sections made it evident that such 
nodules also had formed in relation to vessels passing into the cord alongside the 
emerging nerve bundles, and that the nodule formation took place just as in relation to 
other lateral vessels. The close proximity of the emerging fibres to the nodule made 
it appear as if they entered into and emerged from the nodule. On several occasions, 
however, the emerging strands showed a definite tortuosity in their course. 
According to Nacrorrts (p. 726), the Ausgangspunkt of tabes is formed by an area 
of transverse neuritis, situated near the point where the roots penetrate the dura. It 
has already been pointed out that a retrograde degeneration may occur in the anterior 
roots and that from the point where this may be arrested the anterior roots may 
