MULTIPLE NEUROMATA OF THE CENTRAL NERVOUS SYSTEM. 719 
review of his numerous articles, in which answers to these questions are given with 
the most elaborate detail. We endeavour to present only the main conclusions and 
hint at how they were reached. (1) The ganglion cell of the anterior horn, deprived 
of its axis-cylinder process, cannot form a new nerve process if it is not in connection 
with a cell of the sheath of Schwann. All experiments which seem to prove this 
had always left a considerable part of nerve root with attached Schwann cells, so 
that it was impossible to state how much was to be put down to the central cell 
and how much to the Schwann cell. BrrHE severed the anterior nerve bundle 
just within the pia, thus leaving no sheath of Schwann cells, and found that the 
ganglion cells never produced a new axis-cylinder process. If any sheath of Schwann 
cells were left, z.c. if section was extra-medullary, Berax found that small neuromata 
developed in the pia and that this production was more marked the further from the 
cord section had taken place. Therefore the central end alone cannot produce a 
_ new axis-cylinder process, and the production of the new nerve is in the first degree 
the function of the Schwann cells. (2) In young animals nerve fibres permanently 
severed from their trophic centre, e.g. by the excision of 4-6 cm. of the nerve trunk, 
_ regenerate autogenously and become capable of excitability and conductivity. Brrne 
enclosed the upper end of the distal segment of the cut nerve in a capsule, and in 
_ several other ways avoided the possibility of a connection of the peripheral with the 
central end. He therefore concluded that in young animals the peripheral end could 
regenerate autogenously. In adult animals he admitted that regeneration never 
went beyond the stage of protoplasmic bands, Axzalbandfasern, or embryonic fibres, 
unless union with the central end was effected. He is convinced, however, that the 
growth of the axis-cylinder and myelin sheath in these embryonic fibres is definitely 
a cell differentiation and not an outgrowth from the central end. Brrur’s searching 
criticism of the centralists’ position must be very carefully considered by anyone 
taking up an opposite opinion. It has seemed to us that none of those who during 
the past ten years have sought to answer his objections have sufficiently recognised 
the pains he has taken to fulfil the very conditions they have themselves laid down 
as essential. We can mention only one or two out of many points which Berne 
has emphasised. Casat and PERRoncito, as we shall see later, show that Schwann 
cells form the outermost part of the bulbous end of the young central axis-cylinder, 
and yet claim this fact as supporting the outgrowth theory. Brrue explains this 
as a regeneration proceeding from the proliferation of the last-preserved Schwann 
cells nearest the point cut through. Again, the impossibility of the functional 
reunion of motor and sensory fibres, also of pre-ganglionic and post-ganglionic fibres, 
proves that the remains of the nerve fibres retain, after degeneration is accomplished, 
a certain degree of their specific function. This is against the indifferent character 
attributed by the centralists to the cells of Schwann sheath. 
Fiemine (1902) holds an opinion which he describes as midway between that 
Wt held a the central and peripheral theorists. In numerous sections from the peripheral 
