730 DR ALEXANDER BRUCE AND DR JAMES W. DAWSON ON 
degeneration of both stumps, reach the cicatricial zone and are there arrested by the 
proliferation of the supporting elements. After intra-cranial section of the optic nerve 
the fibres in connection with the central (retinal) cells show during the first month 
considerable regenerative activity. Rosst holds that fibres separated from their central 
cells could not regenerate spontaneously. 
PERRERO (1909) considers that the question of the regeneration of the fibres of the 
central nervous system may be counted as solved, thanks to the methods of CasaL and 
BrELscHowsky. By means of these methods it is possible to avoid the fallacy which 
underlay previous observations of those who used methods which stain axis-cylinder 
and glia fibres alike. PERRERO examined the cord from a man who died with symptoms 
of complete transverse lesion 29 days after fracture of the 5th and 6th cervical 
vertebrae. Immediately above and below the completely softened segments of the 
cord, corresponding to the injured vertebra, numerous formations were found which 
were regarded by the author as undoubted phenomena of regeneration, e.g. divisions 
of fibres, cones, rings, and balls. From some of the terminal balls fine black threads 
could be traced ; other axis-cylinders were found dissociated into fibrils which frequently 
formed a plexus formation around the vessels. ‘These appearances were noted especially 
in relation to the pyramidal fibres of the cord above the lesion and to the posterior 
columns and posterior roots immediately below the lesion. The regeneration was not 
sufficient to pass through the zone of softening. 
(3) GenesIS oF Fipres in Tumour Formation. 
The histogenesis of nerve fibres has been discussed from the developmental aspect 
and from the experimental aspect in the regeneration of the divided nerve, but it has 
very rarely been considered in pathological conditions. Here we have to do not 
with the first development of the embryonal nerve fibre, nor with the restoration of 
the distal end of a severed nerve, but with the new formation of nerve fibres in a 
pathological tissue. Regarding tumours in relation to nerves, we have in general 
two opposite views: the one teaches that the tumours arise from the connective 
tissue and have only a local relation to the nerves; the other accentuates the nervous 
nature of the tumours. 
VIRCHOW, in 1868, as we have already seen, had emphasised the nervous nature 
of these growths, but his views did not gain general acceptance, and the conception 
continued to prevail that the tumours designated by the name “‘ neuroma” arise 
from the connective tissue sheaths and have only a secondary relation to the nerves. 
Von REcCKLINGHAUSEN, in 1882, noted the frequency of the relation of multiple 
neuromata with skin fibromata. He looked upon the tumours as essentially of the 
same structure—fibromata arising in the connective-tissue sheaths of the nerves, 
