748 DR ALEXANDER BRUCE AND DR JAMES W. DAWSON ON 
the fibrosis: the most constant of these were the posterior column sclerosis and the 
area in the direct cerebellar tract. 
To complete the histological picture it is necessary to refer to one very constant 
feature present throughout nearly the whole cord. The intra-medullary course of the 
posterior roots showed a very marked fibrosis. In Weigert preparations, the posterior 
root-entry zones were definitely degenerated, and in Weigert-fuchsin and Van Gieson 
preparations it seemed as if the neurilemma sheath in relation to the posterior roots 
were continued along the fibres right into the root-entry zone for a varying distance 
(fig. 53). The anterior nerve roots in their intra-medullary course also showed this 
change, but to a less extent and less constantly, except in the lumbo-sacral cord 
(fig. 54). 
It will thus be seen that there were several distinct appearances present in the 
cord :— | 
(1) The neuroma nodules, and by neuroma again we refer to all stages in the develop- 
ment of a nodule from a few abnormal fibres in relation to vessels or the pial spaces to 
definite nodule formations ; 
(2) A fibrosis, in varying degrees of extension, involving areas in which neuromata 
had developed ; 
(3) A fibrosis of the intra-medullary portions of the anterior and posterior roots ; 
(4) The sclerosis which seemed independent of the presence of the fibrosis. 
(1) Nopute Formation. 
The detailed description of the nodules will be taken up in the following order :— 
(a) Disposition of the fibres forming the nodules ; 
(6) Structure and mode of formation ; 
(c) Origin of the fibres ; 
(d) Distribution of the nodules. 
A convenient introduction to this study will be given by a brief reference to the 
first microscopic preparations examined. These were Van Gieson-stained paraffin sections 
from the Ist dorsal segment. It will be remembered that the 2nd and 8rd dorsal 
segments were almost typical in appearance, and in this segment the normal architecture 
of the cord was retained with the exception of the presence of two symmetrical areas 
on either side in the white matter immediately adjoining the concave anterior and 
antero-lateral margins of the grey matter. 
On the right side was the isolated oval nodule represented in fig. 19, and on the 
left side a larger nodule, not so defined however. Under high power the nodule on the 
right side was found to be composed of nerve fibres cut transversely, obliquely, and 
longitudinally (cf. fig. 6). The fibres had the structure of a peripheral nerve with 
axis-cylinder, myelin sheath, and neurilemma sheath, and had only a small amount of 
