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MULTIPLE NEUROMATA OF THE CENTRAL NERVOUS SYSTEM. plays 
the developing muscle fibres. It is important also to note that the regeneration 
of the nerve fibres was later than that of the muscle fibres, so that the neuroblasts 
could not be confounded with the developing myoblasts. The authors finally refer to 
the remarkable analogy between nerve fibre and muscle fibre regeneration: an analogy 
to be emphasised by Durante and Lustic. Gatrorrr and Levi later traced the 
development of muscle fibres and nerve fibres in the tail of newly hatched lizards, 
and found that regeneration had proceeded along lines exactly comparable to the 
stages in the first development. 
Kennepy (1897-1904), in the microscopic examination of portions of nerves 
removed previous to secondary suture, found in both central and peripheral ends 
irregularly arranged groups of nerve fibres. The fibres cut longitudinally showed 
a delicate axis-cylinder in the centre, a granular deposit of myelin around it, a 
homogeneous protoplasm zone around the myelin, and oval nuclei arranged at intervals. 
The transversely cut fibres appeared as clearly defined circles, each containing an 
axis-cylinder in the centre and many with an attached nucleus. The arrangement 
of the bundles was very irregular, and there were found transversely cut bundles 
with longitudinal and oblique fibres coursing around them. The enormous number 
of spindle-shaped nuclei amongst the nerve fibres indicated that these elements had 
arisen by proliferation from the nucleus of the sheath of Schwann, and Kennepy believes 
that these new nerve fibres in the peripheral stump of a still-severed nerve—showing 
axis-cylinder and commencing myelination—could have arisen only from the nucleus 
and protoplasm of the interannular segment, which must therefore be regarded as 
a neuroblast. Further steps to complete differentiation of the nerve fibre probably 
depend on a restoration of continuity. A fibre may remain in this incompletely 
differentiated stage for a very long time, and this resting-stage, as it were, affords an 
explanation of the very rapid return of sensation after secondary suture, for the nerve 
path is practically ready to transmit impulses and needs little further differentiation. 
BaLuance and Stewarr (1901) have made a very thorough histological in- 
vestigation of the process of regeneration in nerves after section, both with and 
without suturing of the proximal to the distal segment, and also of the changes which 
occur in nerve grafts. The experiments were carried out on monkeys, dogs, and cats, 
and the histological methods used were very complete :—Weigert’s medullated sheath 
stain, the Golgi and Stroebe methods for axis-cylinders, and Van Gieson’s method 
for cellular and protoplasmic structures. The neurilemma cells commenced to 
proliferate on the second day after section ; the resulting cells preserved the longitudinal 
‘direction of the parent cell, and from their opposite poles sent out fine protoplasmic 
processes. These proliferated neurilemma cells play only a transient rdle in the 
absorption of the fatty débris of the degenerated myelin, and the chief part in 
phagocytosis is carried out by immigrated cells from connective tissue and blood. 
The proliferated neurilemma cells in both central and distal ends take on an active 
neuroblastie function. They secrete short lengths of axis-cylinder which increase 
